| No. & Date Asked | Question |
# 927 :: 2/2
|
A company that manufactures computer chips wants to use a multiple regression model to study the effect that different variables have on y, the total . . . |
# 926 :: 1/30
 |
A survey of random sample of people leaving an amusement park showed an average expenditure number 10.30k for the evening, the average of expenditure . . .
weighted mean |
# 925 :: 1/30
|
3 section of a statistics class containing 28,32 and 35 students averaged 83,80 and 76 respectively on same final exam. what 's the combined populatio. . .
weighted mean |
# 924 :: 1/23
|
Given the sample dataset of size n = 5: {2, -4, 1, 1, 5x}. Note that x is a real number.
Obtain the empirical influence function for the mean an. . . |
# 923 :: 1/23
|
The average life span of American male professors is 75.6 years, but standard deviation is unknown. A
random sample of n = 5 recently (last 10 ye. . . |
# 922 :: 1/23
|
A random sample of measurements on two quantitative variables x and y is taken from a population.
The data for the variables x and y are: {(x,. . . |
# 921 :: 1/23
|
Consider the finite population of size N = 3, measurements on the variable x: {2, 3, 4}:
a. derive the population probability distribution for the . . . |
# 920 :: 1/13
|
The average service time at CheesePlate Restaurant is 3.5 minutes with a standard deviation of .04 minutes. A new order system claims it can improve . . .
1-sample t-test |
# 919 :: 1/12
|
income and daily expense.the two variable will consider as discrete or continuous?. . . |
# 918 :: 1/12
|
what is mode?. . . |
# 916 :: 1/9
|
what is the diffrence betweenqualitative data and nominnnal data?. . . |
# 915 :: 12/6/11
|
create a 95%confidence interval for the value of the population mean, given that their is a sample mean of 49 and a standard deviation of 3 but now fo. . .
1-sample t-test,
Confidence Intervals |
# 914 :: 12/6/11
|
create a 95% confidence interval for the value of the population mean, given that their are 64 observations and a sample mean of 49, with a sample sta. . .
1-sample t-test,
Confidence Intervals |
# 913 :: 12/5/11
|
The mean is 112 oz, and the standard deviation is 40 oz. Compute the probability that the mean from a sample of 49 will fall between 103 and 121 oz. . .
Z-Score,
Area between,
Standard Error of the Mean |
# 912 :: 12/3/11
|
Find the appropriate critical statistic for a two tailed test with 20 observations and alpha equal to 0.05.. . .
Critical Value,
t-statistic |
# 911 :: 12/3/11
|
Find the critical statistic for a one tailed test in the negative direction with 25 observations and alpha equal 0.01.. . .
Critical Value,
t-statistic |
# 910 :: 12/3/11
|
Find the appropriate critical statistic for : A one tailed test in the positive direction with 15 observations with alpha equal to 0.001.. . .
Critical Value,
test statistic |
# 909 :: 12/3/11
|
Find the critical statistic for: A two tailed test with 50 observations with alpha equal to .001.. . .
Critical Value,
t statistic |
# 908 :: 12/3/11
|
Create a 90% confidence interval for the value of the population mean using the following information: A sample mean of 65, a sample standard deviatio. . .
1-sample t-test |
# 907 :: 12/3/11
|
Suppose that you have a sample mean of 49 and a standard deviation of 3, but now found those values from a sample of 20 observations. test the hypothe. . .
1-sample t-test |
# 906 :: 12/3/11
|
You want to test the hypothesis that the mean age for teachers is equal to 50. If you take a sample of 64 observations and find a sample mean of 49, w. . .
1-sample t-test |
# 905 :: 12/3/11
|
create a 95% confidence interval for the value of the population mean using the following information: a sample mean of 55, a sample standard deviatio. . .
Confidence Intervals |
# 904 :: 10/24/11
|
Use MINITAB to generate 1200 individual values from a Standard Normal distribution (mean = 0, std. dev = 1).. . . |
# 903 :: 10/16/11
|
Consider a random sample of 9 observations, from a Normal distribution, with sample average 25.0.
a) Calculate a 95% confidence interval for the p. . . |
# 900 :: 9/28/11
|
Suppose we want to design a new placebo-controlled trial to evaluate an experimental medication to increase lung capacity. The primary outcome is pea. . . |
# 899 :: 9/5/11
|
In a study , the average age of the male candidates who were affected , was 38.20 whereas the average age of the female subjects was calculated to 34. . .
Variance,
Standard Deviation |
# 898 :: 8/1/11
|
Hi,
I believe this question may require a few back n forth emails from us as I'm not sure if I will cover everything that is required for you to an. . . |
# 897 :: 7/27/11
|
What is the probability for the following values of Z?
a. Z < 1.35
b. Z > -1.84 and Z < 2.52
c. Z < 1.02 and Z > 2.77. . .
Area between,
Z-Score |
# 896 :: 7/26/11
|
1. Given the following probability distributions:
Group A
X P(X)
2 0.15
4 0.20
6 0.25
8 0.15
10 0.25
a. Compute the expected v. . .
Expected Value |
# 895 :: 7/19/11
|
In a sample of n = 36 selected from a population, where X = 96 and S = 12, what is the value of tSTAT if you are testing the null hypothesis H0: µ = 1. . .
1-sample t-test,
test statistic |
# 894 :: 7/17/11
|
Can percentages be converted to z score?. . .
Z-Score |
# 893 :: 7/12/11
|
Elbow to fingertip length of men 99% confidence n=32, x- 14.50,s= 0.70 what is the margin of error. . .
Margin of Error,
Confidence Intervals |
# 892 :: 7/11/11
|
42 people judged their emotional response to six typeface designs. There were 12 buttons to present the emotions visually (via animated characters). P. . . |
# 891 :: 6/25/11
|
X, Y, and Z are independent normally distributed random variables. The following information is known about these three variables:
E (X) =4, . . . |
# 890 :: 6/14/11
|
I've a set of related questions on power analysis.
Suppose I have an experiment with 5 groups and 5 DVs and intend to conduct MANOVA to determine . . .
MANOVA,
Power |
# 889 :: 5/29/11
|
2. The figure below is a Normal quantile plot of the emissions of carbon dioxide (CO2) per person in 48 countries. The data set can be found under Ass. . . |
# 888 :: 5/29/11
|
1. Too much cholesterol in the blood increases the risk of heart disease. Young women are generally less afflicted by high cholesterol than other grou. . . |
# 887 :: 5/29/11
|
1. Too much cholesterol in the blood increases the risk of heart disease. Young women are generally less afflicted by high cholesterol than other grou. . . |
# 886 :: 5/2/11
|
ok i will wait for my answer.. . . |
# 885 :: 5/2/11
|
as i study on childhood disease then my collected sample is 269 and variable include age of child ,vaccination status , social condition include type . . . |
# 884 :: 5/1/11
|
1The following data represent the results from an independent-measures study comparing three treatments.
Treatment
I II III
n = 10 n = 10 n = 10
. . . |
# 883 :: 4/1/11
|
In studying satisfaction patients have with an operation I have 2 random groups each given a different questionaire. I want to compare the responses o. . . |
# 882 :: 3/24/11
|
8. For the preceding problem you should find that
there are significant differences among the three
treatments. The primary reason for the significa. . . |
# 881 :: 3/24/11
|
6. The following data represent the results from an
independent-measures study comparing three
treatments.
a. Compute SS for the set of 3 treatment. . . |
# 880 :: 3/24/11
|
Describe the similarities between an F-ratio and a t statistic.. . .
t-statistic,
F-statistic |
# 879 :: 3/14/11
|
What is statistical significance of p-value. . . |
# 878 :: 1/16/11
|
Banner Mattress and Furniture Company wishes to study the number of credit applications received per day for the last 300 days.
To interpret, there. . .
Chi-Square Goodnes of Fit Test,
Poisson Distribution |
# 877 :: 1/13/11
|
Suppose that the sales manager of a large automotive parts distributor wants to estimate as early as April the total annual sales of a region. On the. . .
Regression Analysis |
# 876 :: 1/8/11
|
A suburban hotel derives its gross income from its hotel and restaurant operations. The owners are interested in the relationship between the number o. . .
Scatter Plot,
correlation coefficient |
# 875 :: 1/8/11
|
The amount of income spent on housing is an important component of the cost of living. The total costs of housing for homeowners might include mortgag. . .
Paired t-test |
# 874 :: 1/3/11
|
Martin Motors has in stock three cars of the same make and model. The president would like to compare the gas consumption of the three cars (labeled c. . .
ANOVA |
# 873 :: 1/3/11
|
During recent seasons, Major League Baseball has been criticized for the length of the games. A report indicated that the average game lasts 3 hours a. . .
1-sample t-test |
# 872 :: 12/7/10
|
Discuss how a t Test for a dependent variable can be of great value in applying a new approach to the treatment of aggressive behavior to a small grou. . . |
# 870 :: 11/6/10
|
A hospital in California uses 100.6 degrees Fahrenheit as the lowest temperature considered to indicate a fever. What percentage of normal and health. . .
Z-Score |
# 869 :: 10/14/10
|
You need to estimate the mean Christmas sales across a large chain of jewelry stores. You want to estimate this mean value to within $100 with 99% co. . .
Sample Size |
# 868 :: 10/14/10
|
Suppose that a 90% confidence interval for a population mean μ is constructed from a sample, resulting in the interval from 120 to 150. What was. . .
Confidence Intervals,
Margin of Error |
# 867 :: 10/11/10
|
A manufacturer wants to increase the absorption capacity of a sponge. Based on past data, the average sponge could absorb 3.5 ounces. An organic candl. . . |
# 866 :: 10/9/10
|
A study showed 118 instances of breast cancer among 3,303 mothers who used diethylstibestrol (DES), an estrogen-like substance formerly used to preven. . . |
# 864 :: 4/15/10
|
1. Suppose a 95% confidence interval for the mean daily sales for a sample of 100 days from an internet site is:($236, $318).
a. Will a 99% confidenc. . . |
# 863 :: 4/12/10
|
Describe how measurements and regression analysis are interpretations of reality and not reality itself. (One page answer). . . |
# 862 :: 4/12/10
|
A recent survey of community colleges found the average age of attending students to be 29. A class of 24 students has a mean age of 26 and a standard. . . |
# 861 :: 4/8/10
|
Lab 6, confidence intervals, two sample and paired
In class we discussed GM testing a brake light. Suppose that this is very expensive, time-consum. . . |
# 860 :: 3/30/10
|
Problem # 1:
Clothing for Runners: Your company sells exercise clothing and equipment on the internet. To design the clothing, you collect a data on. . .
Confidence Intervals,
Margin of Error |
# 859 :: 3/18/10
|
1) Spinifex pigeons are one of the few bird species that inhabit the desert of Western Australia. The pigeons rely almost entirely on seeds for food. . . .
Confidence Intervals |
# 858 :: 3/18/10
|
A questionnaire about study habits was given to a random sample of students taking a large introductory statistics class. The sample of 25 students re. . .
Margin of Error |
# 857 :: 3/17/10
|
A drug manufacturing company conducted a survey of customers. The research question is: Is there a significant relationship between packaging preferen. . .
Chi-Square Test of Independence |
# 856 :: 3/14/10
|
In this case, we are going to study some data collected from Kelly Blue Book for several hundred 2005 used General Motors (GM) cars. This data allows . . .
Regression Analysis |
# 855 :: 3/6/10
|
Random samples of five were selected from each of three populations. The sum of
squares total was 100. The sum of squares due to the treatments was 4. . .
ANOVA Summary Data |
# 853 :: 3/6/10
|
A recent study focused on the number of times men and women who live alone buy
take-out dinner in a month. The information is summarized below.
Stat. . .
2-sample z-test |
# 852 :: 3/5/10
|
There are four entrances to the Government Center Building in downtown Philadelphia.
The building maintenance supervisor would like to know if the en. . .
Chi-Square Goodnes of Fit Test |
# 851 :: 3/5/10
|
In a particular market there are three commercial television stations, each with its own
evening news program from 6:00 to 6:30 P.M. According to a r. . .
Chi-Square Test of Independence,
Chi-Square Goodnes of Fit Test |
# 850 :: 3/5/10
|
The following is a partial ANOVA table.
Source sum of Squares df . . .
ANOVA Table,
ANOVA |
# 849 :: 3/5/10
|
A real estate agent in the coastal area of Georgia wants to compare the variation in the
selling price of homes on the oceanfront with those one to t. . .
F-test |
# 848 :: 3/5/10
|
The president of the American Insurance Institute wants to compare the yearly costs of
auto insurance offered by two leading companies. He selects a . . .
Paired t-test |
# 847 :: 3/5/10
|
Grand Strand Family Medical Center is specifically set up to treat minor medical emergencies
for visitors to the Myrtle Beach area. There are two fac. . .
2-sample t-test |
# 846 :: 3/2/10
|
A recent article in The Wall Street Journal reported that the 30-year mortgage rate is now
less than 6 percent. A sample of eight small banks in the . . .
1-sample t-test |
# 845 :: 3/2/10
|
Dole Pineapple, Inc., is concerned that the 16-ounce can of sliced pineapple is being
overfilled. Assume the standard deviation of the process is .03. . .
1-sample t-test,
1-sample Z-test |
# 844 :: 3/2/10
|
A new weight-watching company, Weight Reducers International, advertises that those
who join will lose, on the average, 10 pounds the first two weeks. . .
1-sample t-test,
1-sample Z-test |
# 843 :: 2/27/10
|
Braking distances of cars. A random sample of 13 four-cylinder cars is obtained and braking distances are measured and found to have a mean of 137.5 . . .
Standard Deviation,
Two Variances,
F-statistic |
# 842 :: 2/18/10
|
what statistic method is best used to test 'the influence of persons on behaviour of other persons?
thank you.. . . |
# 840 :: 2/11/10
|
Sat verbal scores are normally distributed with a mean of 426 and a standard deviation of 94. Use the Empirical Rule to determine what percent of the. . .
Empirical Rule |
# 838 :: 2/9/10
|
using the full 5-step process test to see if a population mean is not 25. Sample data is: Mean 24, standard deviation 10 and a sample of 400 was taken. . .
1-sample t-test |
# 836 :: 1/13/10
|
a statistician was setting up a hypothesis test with a level of significance dictated by upper management. However, she was concerned that the test wo. . .
Type II Error,
Sample Size |
# 835 :: 12/12/09
|
• Analyze the following two data sets:
o In Statistics Alive, Module 35, p. 410–411, data are presented for 15 persons regarding high. . . |
# 834 :: 12/9/09
|
You are interested in testing the hypothesis that men have greater levels of political participation than women, so you survey 332 men and 375 women . . .
2-sample t-test,
Hypothesis Test |
# 833 :: 12/9/09
|
suppose that the census indicates the average American earns $36,345.45 per year. You are interested in the whether people who majored in political s. . .
Hypothesis Test,
1-sample t-test |
# 832 :: 12/8/09
|
1.What are the underlying assumptions of Spearman rank-order scale?
2.What happens when a stanine is more than 9?Explain.. . . |
# 831 :: 12/3/09
|
I have a humor appreciation survey with 40 items and 500 participants. The items were interpreted and classified by a theory into four classes of 10 i. . . |
# 830 :: 11/24/09
|
A psychologist is studying the distribution of IQ scores of girls at an alternative high school. In wishing to estimate the average IQ scores in this . . . |
# 824 :: 11/8/09
|
The grades on a statistics midterm test are normally distributed with a mean of 78 and a standard deviation of 6
a. What proportion of the class has . . .
Z-Score,
Standard Error of the Mean |
# 823 :: 10/22/09
|
What is an 'effect size' ? When is it used ? Why is it used in educational research?. . .
Effect Size,
Cohen d |
# 822 :: 10/19/09
|
Jeff... the previous answer was not quite the answer I was anticipating- let me restate the problem more clearly.
1. A manufacturer has a process whi. . . |
# 821 :: 10/18/09
|
A manufacturer can typically process 176-264 devices a given period of concern. In this situation the processing event is either pass or fail. There i. . .
Power,
Sample Size,
Effect Size,
1-Proportion Test |
# 820 :: 10/17/09
|
An animal trainer obtained the following sample data (Table A) in a study of reaction times of dogs (in seconds) to a specific stimulus. He then selec. . .
Standard Deviation,
Standard Deviation on Frequency Data,
Standard Deviation of Grouped Data,
F-test |
# 819 :: 10/15/09
|
For a particular sample of 50 scores on a psychology exam, the following results were obtained.
First quartile = 52 Third quartile = 84 Standard dev. . .
Chebyshev's Theorem,
Midrange,
Empirical Rule |
# 817 :: 10/8/09
|
1) Assuming in New York 80% of women and 50% of men know where Tiffany is. At a crossing I ask pedestrians for directions to Tiffany and get these ans. . .
Binomial Probability |
# 815 :: 10/5/09
|
Shaver Manufacturing, Inc., offers dental insurance to its employees. A recent study by the human resource director shows the annual cost per employee. . .
Z-Score,
Area between |
# 814 :: 10/4/09
|
in a school how is ztest used in time table ... one group that studies 7 periods a day of 45 mins each class and the other group can choose semester w. . .
2-sample z-test,
2-sample t-test |
# 813 :: 10/2/09
|
Serum cholesterol levels were taken from a population of 10,000 college students. The results were normally distributed. Males had a mean of 195 and a. . .
Z-Score,
NORMSDIST |
# 812 :: 10/2/09
|
A Tamiami shearing machine is producing 10 percent defective pieces, which is abnormally high. The quality control engineer has been checking the outp. . .
BINOMDIST,
Binomial Probability |
# 811 :: 10/1/09
|
Discuss the assumptions for using a chi-square test. Research articles using and provide practical examples from the reseach to support your assumptio. . . |
# 806 :: 9/7/09
|
Discuss how the statistical application of Pearson r is used for hypothesis testing.l Through application of the Spearman Correlation discuss what ty. . .
Pearson r,
Spearman Correlation |
# 804 :: 8/29/09
|
The mean on this test is 3.5 with a standard deviation of .5. Sally scores 1.5 on this test. How many standard deviations is Sally from the mean?. . .
Z-Score |
# 803 :: 8/28/09
|
In a study, the sum of squared deviations from the mean for the sample is 12 and there are 4 participants. What is the estimated population variance?. . .
Variance |
# 802 :: 8/27/09
|
type of research where using the t statistic may be an appropriate alternative to using a z-score. . .
t statistic |
# 798 :: 8/19/09
|
Teens were asked in the MTF 2006 survey how often they think about social issues (specific issues were not identified). The bivariate table includes r. . .
Chi-Square,
Chi-Square Test of Independence |
# 797 :: 8/15/09
|
The issue of how much should be spent to solve particular U.S. social problems is a complex matter, and people have diverse and conflicting ideas on t. . .
Chi-Square |
# 796 :: 8/13/09
|
Very happy Not happy at all
Mean ideal number of children 3.32 2.07
Standard deviation . . .
2-sample t-test |
# 795 :: 8/13/09
|
Data from the MTF 2006 survey reveal that 71.5% (432 out of 604) of males and 74% (562 out of 756) of females reported trying alcohol. You wonder whe. . .
2-proportion test |
# 794 :: 8/10/09
|
A psychologist has developed a test to measure self-control. The test is normed so that it has a mean of 100 and a standard deviation of 15... The s. . .
Z-Score,
Percent Score,
Percentile Rank,
Area between |
# 793 :: 8/8/09
|
For the total population of a large southern city, mean family income is $34000, with a standard deviation (for the population) of $5000.
a. imagi. . .
Z-Score |
# 792 :: 8/7/09
|
send the standard normal table. . . |
# 791 :: 8/4/09
|
Serum cholesterol levels were taken from a population of 10,000 college students. The results were normally distributed. Males had a mean of 195 and a. . .
Z-Score |
# 790 :: 7/31/09
|
As a condition of employment, Fashion Industries applicants must pass a drug test. Of the last 220 applicants 14 failed the test. Develop a 99 percent. . . |
# 789 :: 7/31/09
|
A state meat inspector in Iowa has been given the assignment of estimating the mean net weight of packages of ground chuck labeled “3 pounds.” Of cour. . . |
# 788 :: 7/31/09
|
A recent survey of 50 executives who were laid off from their previous position revealed it took a mean of 26 weeks for them to find another position.. . . |
# 787 :: 7/30/09
|
Below are fertility rates (average children born per woman) in 15 EU nations for 2 years. (a) Make
a scatter plot. (b) Find the correlation coefficie. . .
correlation coefficient ,
significant correlation,
Pearson r |
# 786 :: 7/27/09
|
From her firm’s computer telephone log, an executive found that the mean length of 64 telephone
calls during July was 4.48 minutes with a standard de. . .
2-sample t-test |
# 784 :: 7/21/09
|
Two manufacturing facilities produce 1280 × 1024 LED (light-emitting diode) displays. Twelve
displays are chosen at random from each lab, and the num. . .
Mann Whitney |
# 782 :: 7/14/09
|
A 20-minute consumer survey mailed to 500 adults aged 25–34 included a $5 Starbucks gift certificate.
The same survey was mailed to 500 adults aged 2. . .
2-proportion test |
# 781 :: 7/14/09
|
I am to do a study that involves people whose IQ are in the normal range 70 to 130. How many people must I screen with IQ test in order to find a samp. . .
Sample Size |
# 780 :: 7/14/09
|
Dear Mr. Sauro:
In reference to you article, "Calculating a Sigma Level from Task Success," I found no references to “usability” nor “task completio. . .
Usability,
Six Sigma |
# 779 :: 7/13/09
|
If all the values in a set are converted to z-scores, is the shape of the distribution of the z scores will be bell shape regardless of the distributi. . .
Central Limit Theorem |
# 778 :: 7/12/09
|
200 students took a test. The scores were normally distributed. Your score was in the 60th percentile. How many people scored at or below your score?. . .
Percentile |
# 777 :: 7/11/09
|
Suppose that the quarterly sales levels among health care information systems companies are approximately normally distributed with a mean of million. . . |
# 776 :: 7/8/09
|
Clients at a Diabetic Education Program were randomly assigned to one of two learning programs.
Group A participants attended a three-day, in-class. . . |
# 775 :: 7/6/09
|
1.-A state meat inspector in Iowa has been given the assignment of estimating the mean net weight of packages of ground chuck labeled “3 pounds.” Of c. . .
Confidence Intervals |
# 774 :: 7/5/09
|
If I'm doing a multivariate linear regression in Minitab (about 40 variables), how to restrict all coefficients positive?. . .
Linear Regression |
# 773 :: 7/1/09
|
i have problem in run multiple linear regression which faced me a problem of heteroscadecity and i want solve it using weight least squares (wls) but . . . |
# 772 :: 6/29/09
|
A random sample of 16 pharmacy customers showed the waiting times below (in minutes). Find a 90 percent confidence interval for μ, assuming that the . . . |
# 771 :: 6/29/09
|
One-fourth of the residents of the Burning Ridge Estates leave their garage doors open when they are away from home. The local chief of police estimat. . .
Bayes Theorem ,
Conditional Probability,
Tree Diagram |
# 770 :: 6/29/09
|
Dr. Stallter has been teaching basic statistics for many years. She knows that 80 percent of the students will complete the assigned problems. She has. . .
Bayes Theorem ,
Tree Diagram |
# 768 :: 6/26/09
|
A multiple choice test consists of 25 questions with possible answers of a, b, c, d, and e. Estimate the probability that with random guessing, the nu. . .
Binomial pmf |
# 767 :: 6/24/09
|
IQ scores are normally distributed with a mean of 100 and a std dev of 15. If 25 people are randomly selected for an IQ test, find the probably that . . .
Z-Score |
# 766 :: 6/23/09
|
A researcher has a series of Likert-scaled items and a measure of frequency of absenteeism. He uses each of the Likert-scaled items in a separate biva. . .
Correlation,
Non-Linear Correlation |
# 765 :: 6/23/09
|
A football team's season ticket sales, percentage of games won, and number of active alumni for the years 1992-2000 are given below:
Year . . .
Regression Analysis |
# 764 :: 6/23/09
|
Suppose Abraham Lincoln had answered a survey questionnaire in which he indicated that he had not received a grade school diploma. The researcher foun. . .
Correlation |
# 763 :: 6/18/09
|
Finding appropriate z- and t-scores is important when constructing confidence intervals. Confidence intervals allow one to estimate important populat. . . |
# 762 :: 6/18/09
|
Bob enjoys making candy and some friends have encouraged him to open a candy-making business. To see if the local citizens buy enough candy, Bob gath. . . |
# 761 :: 6/18/09
|
I need to know which formulas would be used to answer these two probability questions.
1. A certain airplane has two independent alternators to prov. . . |
# 760 :: 6/17/09
|
. You are a researcher who conducted a study of soft-drink preferences among residents in a test market prior to an advertising campaign for a new co. . . |
# 759 :: 6/15/09
|
A sample of 25 concession stand purchases at the May 12 matinee of Spider-Man 3 showed a mean purchase of $ 7.29 with a standard deviation of $ 3.02. . . . |
# 758 :: 6/15/09
|
To test the hypothesis that students who finish an exam first get better grades, Professor Hardtack kept track of the order in which papers were hande. . . |
# 756 :: 6/15/09
|
In Dallas some fire trucks were painted yellow (instead of red) to heighten their visibility. During a test period, the fleet of red fire trucks made. . . |
# 755 :: 6/14/09
|
Interpret the following SPSS computer output for the chi-square test. Variable COMMUTE is “How did you get to work last week?” Variable GENDER is “Are. . .
Chi-Square Test of Independence,
SPSS |
# 754 :: 6/14/09
|
Collapse the response categories in the following table so that it meets the assumption of the chi-square test; then perform the test.
. . .
Chi-Square Test of Independence |
# 753 :: 6/14/09
|
Perform a chi-square test on the following data:
(a) Regulation is the best way to ensure a safe workplace.
. . . |
# 752 :: 6/14/09
|
An Excel Spreadsheet is reprinted below. Interpret the t-test results. Are they statistically significant?
t-Test: Paired Two Sample for Means
Be. . .
Paired t-test |
# 751 :: 6/14/09
|
The managers in a company’s East and West regions were rated on the basis of the company’s evaluation system. A researcher wishes to conduct a t-test . . .
2-sample t-test |
# 750 :: 6/14/09
|
Test the hypothesis of no differences for average payback period (years) necessary to justify solar heating systems for residences.
Savings and Loa. . . |
# 749 :: 6/14/09
|
A personnel manager has a computer-generated list of all employees that indicates that 70 percent are full-time employees, 20 percent are part-time em. . .
Chi-Square Goodnes of Fit Test |
# 748 :: 6/14/09
|
What test of differences is appropriate in each of the following situations? Why?
(a) Average campaign contributions of Democrats, Republicans, and. . . |
# 747 :: 6/13/09
|
A random sample of 46 observations was selected from a normally distributed population. The sample mean was xbar=81, and the sample variance was s2=3. . . |
# 746 :: 6/12/09
|
a. Select a variable. Compare the mean of the variable for a sample of 30 for one group with the mean of the variable for a sample of 30 for a second . . . |
# 745 :: 6/8/09
|
Calculate the average student score necessary for the district to retain its federal funding. You may assume that the Standard Deviation will not chan. . . |
# 744 :: 6/6/09
|
Quality Motors is an automobile dealership that regularly advertises in its local market area. It claims that a certain make and model of car averages. . .
1-sample t-test |
# 743 :: 6/6/09
|
Assume you have the following data: Ho: u = 2,450, S = 400, n = 100, and X = 2,300. Conduct a hypothesis test at the .01 significance level.
**If the. . .
1-sample Z-test |
# 741 :: 6/6/09
|
Assume you have the following data: Ho: u = 200, S = 30, n = 64, and X = 218. Conduct a two-tailed hypothesis test at the .05 significance level.. . .
1-sample Z-test |
# 740 :: 6/6/09
|
After a bumper crop, a mushroom grower hypothesizes that mushrooms will remain at the average wholesale price of $1 per pound. State the null hypothes. . . |
# 739 :: 6/4/09
|
How many data do we need as a minimum in order to calculate the z-score meaningfully?. . .
Z-Score |
# 738 :: 6/4/09
|
What value would be needed to complete the following probability distribution?
x p (x)
0 . . .
Random Variable,
Expected Value |
# 737 :: 5/31/09
|
(a) Choose one beverage category and plot the data (MILK CATAGORY CHOSEN). (b) Describe the trend (if any) and discuss
possible causes. (c) Would a f. . .
Time-Series |
# 736 :: 5/28/09
|
A student heard that the average household watches 26.4 hours of t.v. per week, with a stand.dev. of 2.3 hours. He decided to run his own experiment . . .
1-sample Z-test |
# 735 :: 5/25/09
|
how does a confidence interval this relate to learning statistics
How do you think confidence intervals are useful in the real-world?. . .
Confidence Intervals |
# 733 :: 5/24/09
|
The data in the following tables are some of the results of an Internal Revenue Service survey of taxpayers. Analyze and interpret the data.
-The las. . . |
# 732 :: 5/23/09
|
You have asked to research the high absenteeism rate in your company. One required analysis is to be by gender. Assume you have been asked to do the . . . |
# 731 :: 5/23/09
|
Test to see if four population means are the same or different. Assume the populations are normally distributed and have equal variances. Use the fo. . .
ANOVA Summary Data |
# 730 :: 5/23/09
|
Describe the steps in formal hypothesis testing. Make at least one comment for each step.. . .
Steps in Hypothesis Test,
Hypothesis Test |
# 729 :: 5/23/09
|
I want to prove that a population mean is not 150. Use an alpha of 5% and set up the full, detailed, five step hypothesis test. Assume when the sampl. . .
1-sample t-test |
# 728 :: 5/23/09
|
What hypothesis testing model (my “models” handout) would be used under each of the following conditions. Use the “model number” from my handout if y. . .
Statistical Model,
test statistic |
# 727 :: 5/23/09
|
Interpret the following table showing the percentage of individuals on a low-fat or low-cholesterol diet by gender and age.
Age Group Women. . . |
# 723 :: 5/5/09
|
Using this research question and data, perform a nonparametric hypothesis test (Part A and B).
Research Question: Is the average age greater than 4. . .
Sign Test,
Mann Whitney |
# 722 :: 5/5/09
|
What is the definition of an "independent" variable? A dependent variable?
What about a variable I intend to use to help do some forecasting. Int. . .
Scatter Plot,
Scatter Diagram,
Independent Variable,
Dependent Variable |
# 721 :: 5/5/09
|
What does regression do? What is its purpose?. . .
Regression Analysis |
# 720 :: 5/5/09
|
City Opera, a local opera company, wishes to take a sample of its subscribers to learn the average number of years people have been subscribing. The d. . .
Sample Size |
# 718 :: 5/5/09
|
The state of Texas college admission board has set a standard for automatic acceptances to any university at top 10% of any graduating class will be a. . .
Z-Score |
# 716 :: 5/5/09
|
The rockets are playing Lakers tonight in basketball. The lakers average 90 points a game, with a SD of 10. What would the rockets need to score to be. . .
Z-Score |
# 715 :: 5/5/09
|
university of texas will accept all students that have a GPA in the top 10% at their school. At yates the school GPA average is 3.0(on a 4.0 scale) wi. . .
Z-Score |
# 714 :: 5/5/09
|
The mean score on a math test at milby high school was 50. the standard deviation was 10. If the same test was administered to the entire school distr. . .
Z-Score |
# 713 :: 5/3/09
|
Do students at various colleges differ in how sociable they are? Twenty-five students were randomly selected from each of three colleges in a particul. . .
ANOVA,
Eta-Squared,
Effect Size,
ANOVA Summary Data |
# 712 :: 5/3/09
|
Make up a scatter diagram with 10 dots for each of the following situations: (a) perfect positive linear correlation, (b) large but not perfect positi. . .
Scatter Diagram,
Correlation,
Curvilinear Correlation |
# 711 :: 5/3/09
|
Four research participants take a test of manual dexterity (high scores mean better dexterity) and an anxiety test (high scores mean more anxiety). Th. . . |
# 710 :: 4/30/09
|
Discuss how the statistical application of Pearson r is used for hypothesis testing. Through application of the Spearman Correlation discuss what typ. . .
Correlation,
Pearson r,
Spearman Correlation |
# 709 :: 4/30/09
|
Discuss which analysis of variance should be applied when an experiment has more than one independent variable. Discuss the assumptions and limitation. . .
ANOVA,
Factorial ANOVA,
2-Way ANOVA |
# 708 :: 4/30/09
|
Standardized scores offers a way of comparing norm-referenced scores. The z-score distribution is based on knowing how many standard deviations away f. . .
Z-Score,
t-score,
Percentile Rank |
# 707 :: 4/29/09
|
Would you be able to assist me in completing a 5 step hypothesis test on both hypotheses (1 parameter & another with 2 or more)? In completing this t. . .
Five Step Hypothesis Testing,
Parameter |
# 706 :: 4/28/09
|
What is a chi-squared test used for? What is the typical null and alternate hypothesis when doing a chi-squared test?. . .
Chi-Square |
# 705 :: 4/27/09
|
THIS QUESTION IS NO LONGER AVAILABLE. . .
1-sample Z-test |
# 703 :: 4/26/09
|
The following data is a random sample of 1st quiz scores from previous Research 342 classes.
9.5, 6.5, 4.25, 8.5, 7.5, 4.5, 4.25, 6, 7
mean = 6.44 . . .
Confidence Intervals |
# 702 :: 4/26/09
|
A random sample of 100 students who took a statistics exam were asked their score on the exam. The mean score on the test was 50; the standard deviat. . .
Z-Score,
Area between |
# 701 :: 4/26/09
|
A local bakery determines that the probability of a customer ordering a blueberry muffin is 50%. 5 customers come into the bakery.
A. What is the pr. . .
BINOMDIST,
Binomial pmf,
Binomial Probability |
# 700 :: 4/26/09
|
2) Assume the following summary statistics, which describe the speed of a computer processor, are available from a sample of Intel Pentium IV chips ma. . .
Chebyshev's Theorem |
# 699 :: 4/26/09
|
1) The following are the first Quiz scores from a previous RES 341 class:
9.5, 7.5, 9.5, 7, 10, 7.5, 6.5, 1.5, 8, 10
A. Is this data discrete or co. . .
Continuous Data |
# 698 :: 4/26/09
|
A random sample of 10 miniature Tootsie Rolls was taken from a bag. Each piece was weighed on
a very accurate scale. The results in grams were
3.087. . . |
# 697 :: 4/25/09
|
A random sample of 30 executives from companies with assets over $1 million was selected and asked for their annual income and level of education. Th. . .
ANOVA,
Seasonal Data |
# 695 :: 4/24/09
|
I need help with the following.
(A) Develop one business research question
(B) Formulate a research hypothesis to test one population parameter an. . .
Parameter |
# 694 :: 4/21/09
|
Suppose you conduct a study and find that the probability of having a baby boy is 60%. Now suppose three of your relatives are going to have babies. . . . |
# 693 :: 4/21/09
|
Given a single deck of cards, what is the probability of drawing either a king or a diamond? Hint - There are four kings in a deck and 13 diamonds. T. . .
Union,
Probability,
Joint Probability |
# 692 :: 4/21/09
|
Create a Histogram of the following data:
Interval Frequency
0 - 5 0
5 - 10 5
10 - 15 5
15 - 20 15
20 - 25 5
25 – . . . |
# 691 :: 4/21/09
|
Calculate the Standard Deviation of the following list of data: 6, 7, 8, 9, 10. . .
Standard Deviation |
# 689 :: 4/20/09
|
Accounting procedures allow a business to evaluate their inventory at LIFO (Last In First Out) or FIFO (First In First Out). A manufacturer evaluated. . .
Paired t-test |
# 687 :: 4/18/09
|
I would like to determine whether Meijer or Kroger has lower prices on average for families.
I randomly speak with 100 customers who are purchasing g. . .
Independent Sample |
# 686 :: 4/18/09
|
A label on a container of orange juice claims that the orange juice contains an average of 2 grams of fat with standard deviation of 1.5 grams. A cons. . .
1-sample Z-test |
# 685 :: 4/18/09
|
NKU needs to estimate the mean number of hours that all students work to earn money, on average, per week during the full semesters (fall and spring).. . .
Sample Size,
Margin of Error |
# 684 :: 4/18/09
|
Tax companies imply that the returns they prepare are perfect, but what proportion of returns from tax companies have mistakes? To answer this questio. . .
Confidence Intervals,
Confidence Interval around a Proportion |
# 683 :: 4/18/09
|
A baseball fan would like to estimate the mean time it takes to complete a major league baseball game. He randomly selects 40 game lengths (times to c. . .
Confidence Intervals |
# 682 :: 4/17/09
|
Explain the difference between testing a single mean and testing the difference between two means. What two assumptions must be met when one is using . . .
Difference between means |
# 681 :: 4/17/09
|
If two independent samples are used in a hypothesis test concerning the difference between population means for which the combined degrees of freedom . . .
Degrees of Freedom |
# 680 :: 4/17/09
|
To test the null hypothesis that the mean waist size for males under 40 years equals 34 inches versus the hypothesis that the mean differs from 34, th. . .
test statistic |
# 679 :: 4/17/09
|
State the null hypothesis, Ho,and the alternative hypothesis, Ha , that would be used to test the claim: The standard deviation has increased from its. . .
Null Hypothesis ,
Alternative Hypothesis |
# 678 :: 4/17/09
|
A particular candidate claims she has the support of at least 60% of the voters in her district. A random sample of 150 voters yields 87 who support h. . .
test statistic,
Normal Approximation to Binomial |
# 677 :: 4/17/09
|
A random sample of 51 observations was selected from a normally distributed population. The sample mean was x = 88.6 , and the sample variance was s2 . . .
Chi-Square,
Standard Deviation,
Population Standard Deviation,
sample variance,
sampe standard deviation |
# 676 :: 4/17/09
|
Consider testing Ho: μd ≤ 0 vs. Ha: μd = > 0 with n =20 and t∗ =1.95.
Place bounds on the p-value using the table of “critical. . .
Student-t,
Student’s t-distribution,
Critical Value |
# 675 :: 4/17/09
|
A group of sheep, infested with tapeworms, are randomly divided into two groups as follows. Each sheep is assigned a number (1 through 20) and then 10. . .
Dependent Sample,
Independent Sample |
# 674 :: 4/17/09
|
In what ways is the t distribution similar to the standard normal distribution? In what ways is the t distribution different from the standard normal . . .
t-distribution,
Standard Normal Distribution |
# 673 :: 4/16/09
|
Classify the following as independent or dependent samples:
a. Weights of identical twins
b. The effectiveness of two different brands of ibuprofen. . .
Dependent Sample,
Independent Sample |
# 672 :: 4/13/09
|
In Meijer supermarket, the customer's waiting time to check out is approximately normally distributed with a standard deviation of 2.5 minutes. A samp. . .
Hypothesis Test |
# 671 :: 4/13/09
|
A statistician was testing the following hypotheses:
Ho: μ = 500 vs. Ha: μ ≠ 500.
The p-value approach was to be used. A sample . . . |
# 670 :: 4/13/09
|
Assume that z is the test statistic and calculate the value of z∗ for testing the null hypothesis Ho: μ =150.0 when σ = 4.5, n=15, x(b. . .
test statistic,
z-test |
# 669 :: 4/13/09
|
You have failed to reject the null hypothesis when it is false, and therefore you have made a
A) Type A correct decision.
B) Type B corr. . .
Type I Error,
Type II Error,
Hypothesis Test |
# 668 :: 4/13/09
|
Which of the following is the probability of making a Type I error?
A) α
B) 1 - α
C) β
D) 1 - β. . .
Type I Error,
Type II Error |
# 667 :: 4/11/09
|
If the p-value is greater than the level of significance α , then the decision must be to reject Ho.
A) True
B) False. . .
p-value,
Hypothesis Test |
# 664 :: 4/11/09
|
If our decision in a hypothesis test is to fail to reject the null hypothesis, then we know that the null hypothesis must be true.
A) True
. . .
Null Hypothesis |
# 663 :: 4/11/09
|
When we reject the null hypothesis, we are certain that the null hypothesis is false.
A) True
B) False. . .
Null Hypothesis |
# 662 :: 3/23/09
|
I need the formula to calculate z-score. My input is: Base Sample Size, Target Sample Size, Base Proportion, Target Proportion. I have a calculator . . .
2-proportion test |
# 661 :: 3/19/09
|
A student is taking a 10 question multiple choice quiz. There are four possible answers to each question. The student decides to guess at random on al. . .
BINOMDIST |
# 660 :: 3/18/09
|
Four cards are selected, one at a time, from a standard deck of 52 cards. Let x represent the number of aces drawn in a set of 4 cards.
If this expe. . .
Binomial Probability |
# 659 :: 3/18/09
|
Suppose that A and B are mutually exclusive events, and that P(A) = 0.4 and P(B) = 0.3. Then, P(A and B) will be:
A) 0.0
B) 0.4
C) 0.3
D) 0.7. . . |
# 658 :: 3/18/09
|
Under certain conditions, it is possible that the sum of the probabilities of all the sample points in a sample space is less than one.
A) Tru. . . |
# 657 :: 3/18/09
|
If events A and B are not mutually exclusive, they may be either independent or dependent.
A) True
B) False. . . |
# 653 :: 3/11/09
|
What is the cost of a telephone call (per dollar) using a calling card that follows the formula below for a 20-minute call. Cost = 0.50 + 0.15 Minute. . . |
# 651 :: 3/9/09
|
For a population with a mean of 80 and standard deviation of 12, what is the z-score corresponding to x=71?. . . |
# 650 :: 3/9/09
|
2. Your company makes ice cream (178 flavors!) and has just acquired a distribution company with lots of ice cream trucks. You will use their trucks. . . |
# 648 :: 3/7/09
|
A financial planner wants to compare the yield of income- and growth-oriented mutual funds. Fifty thousand dollars is invested in each of a sample of. . . |
# 644 :: 3/3/09
|
An aptitude test has a mean of 220 and standard deviation of 10. find the corresponding z score for: a) a test score of 232 b) a test score of 212. . .
Z-Score |
# 642 :: 3/2/09
|
You are a purchasing agent at a major manufacturing company. You have several hundred business cards from sales reps who have visited you, and you ha. . . |
# 641 :: 3/2/09
|
In general, what is a “Critical Value” or “Cut-Off Score” of a test statistic. . .
Critical Value,
test statistic |
# 639 :: 2/28/09
|
CherryBerry Soda, Inc. claims that 15 percent of the population can identify its products. In efforts to boost their identity, CherryBerry employs a f. . .
Normal Approximation to Binomial ,
1-Proportion Test |
# 638 :: 2/23/09
|
To test the null hypothesis that the mean waist size for males under 40 years equals 34 inches versus the hypothesis that the mean differs from 34, th. . .
1-sample t-test |
# 637 :: 2/22/09
|
Hi Jeff thanks for all your help so far, your answers have been great and very timely. It is great to be able have help from someone with great profes. . .
Adjusted Wald,
Confidence Intervals |
# 635 :: 2/22/09
|
Linemarking for parking bays shall be determined by the retroreflectivity performance of glass beads in the linemarking. The linemarking average level. . .
1-sample t-test,
Confidence Intervals |
# 634 :: 2/20/09
|
A contractor is responsible for drainage network cleaning and shall ensure that the required level of service is achieved. The required level of servi. . .
1-Sample Proportion Test |
# 633 :: 2/20/09
|
Roadmarking shall be determined by the retroreflectivity performance of glass beads in the road marking. The roadmarking average level of reflectivity. . . |
# 632 :: 2/19/09
|
An automobile manufacturer wants to estimate the mean gasoline mileage that its customers will obtain with its new compact model. How many sample runs. . .
Sample Size,
Margin of Error |
# 631 :: 2/19/09
|
My company has been arguing over this topic for quite a while, and I'm looking to put an end to this mathematical question.
We are an ad agency who. . .
A/B Testing,
Response Rates |
# 630 :: 2/19/09
|
Pretend that you are a Finance person in a large dynamic company. Your dream is to become CFO someday, so you want to make good financial decisions. Y. . . |
# 629 :: 2/17/09
|
The following data show samples of three chain stores in three different locations in one town and the amount of dollars spent per customer per visit.. . .
ANOVA |
# 628 :: 2/16/09
|
I have a standard normal distribution with Mean 130, Stdev 8 for school X and a normal distribution for 120 and 10 for school Y. If we select 1 studen. . . |
# 627 :: 2/16/09
|
I have two questions. Thanks for answering them.
(1)A sports enthusiast created an equation to predict Victories (the team’s number of victories in. . . |
# 626 :: 2/15/09
|
Greetings,
My name is Dave Thompson and I work with the Conasauga Drug Court Treatment program in Dalton, GA. I am a Field Practicum Instructor f. . . |
# 625 :: 2/11/09
|
Mean output of solar cells of three types are measured six times under random light intensity over a period of 5 minutes, yielding the results shown. . . .
ANOVA |
# 623 :: 2/9/09
|
The following table lists the number of U.S. mainland hurricane strikes (from 1900 to 1996) for various intensities according to the Saffir-Simpson Hu. . .
Random Variable,
Probability Distribution |
# 622 :: 2/9/09
|
1. If the daily stock price, x, of United Technology is normally distributed with mean 6.56 and standard deviation 2.4, calculate the probability that. . . |
# 621 :: 2/8/09
|
Consider a sample with data values of 10,20,12,17, and 16. Compute the z-score for each of the five observations. . .
Z-Score |
# 620 :: 2/8/09
|
The total area under the curve of the standard normal distribution is not necessarily 1.0.
A) True
B) False. . .
Normal Curve,
Standard Normal Distribution,
Standard Normal Curve |
# 619 :: 2/8/09
|
Suppose the annual consumption of chicken mean is 20.84 pounds per person, and that the standard deviation for the consumption of chicken per person i. . .
Central Limit Theorem |
# 618 :: 2/8/09
|
Individual scores of a placement examination are normally distributed with a mean of 84.2 and a standard deviation of 12.8.
If a random sample of s. . .
Z-Score,
t-score |
# 616 :: 2/7/09
|
Evolutionary theories often emphasize that humans have adapted to their physical environment. One such theory hypothesizes that people should spontane. . .
1-sample t-test |
# 613 :: 2/7/09
|
I am confused on how to calculate a z-score. I am doing a six sigma project right now and am lost on doing the z-score. Here is the information I am p. . .
Z-Score |
# 611 :: 2/5/09
|
6.) For the following set of data, find the linear regression equation for predicting Y from X:
X Y
0 9 . . .
Regression Equation |
# 600 :: 1/30/09
|
True or False
The moving average method averages out cyclical and irregular components.
When using Chi Square , the sum of the expected freque. . .
ANOVA,
Chi-Square,
Goodnees of Fit,
F distribution |
# 599 :: 1/30/09
|
There are two major tests of readiness for college, the ACT and the SAT. ACT scores are reported on a scale from 1 to 36. The distribution of ACT scor. . .
Z-Score,
SAT Scores,
ACT Scores |
# 597 :: 1/30/09
|
TRUE OR FALSE
1. ANOVA is used when we want to know if more than two population means are equal.
2. The sum of the squares error measures the vari. . .
ANOVA |
# 589 :: 1/26/09
|
Apply the Law of Large Numbers: Explain how the following scenario is possible using a coin toss and fictitious data: As the number of trials increase. . .
Law of Large Numbers |
# 588 :: 1/26/09
|
An aptitude test has a mean of 220 and standard deviation of 10. find the corresponding z score for: a) a test score of 232. . .
Z-Score |
# 587 :: 1/26/09
|
True or False
Generally speaking, the Null Hypothesis is set up for the purpose of either accepting or rejecting it.
If the Null Hypothesis is fal. . .
Null Hypothesis ,
Alternative Hypothesis |
# 581 :: 1/21/09
|
hi, I hope you can help me ?
I have 30 variables that i wanted to sort them under 5 known groups . the data came from interviews where i collected . . . |
# 580 :: 1/21/09
|
Conduct the equivalent, nonparametric test of hypothesis using the 5-step process.
MLB � Higher Salaries equate to more home runs per team (Using . . . |
# 576 :: 1/16/09
|
TRUE or FALSE
The level of significance is the probability that a true hypothesis is rejected.
A Type one error is also referred to as an alpha r. . .
Hypothesis Test,
Alternative Hypothesis ,
Alpha,
Null Hypothesis |
# 574 :: 1/14/09
|
Assume you have the following data: Ho mu = 200, s = 30, n = 64, and x-bar
= 218. Conduct a hypothesis test at the .05 significance level.
Assum. . .
1-sample t-test,
1-sample Z-test |
# 572 :: 1/13/09
|
At one university, students are given z-scores at the end of the semester rather than the traditional GPAs. The mean and standard deviation of all stu. . .
Empirical Rule,
Z-Score |
# 571 :: 1/10/09
|
Dr Zak developed a test to measure depression. He sampled 100 university students to take his five item test. The group of students was comprised of 3. . .
Z-Score,
Standard Score |
# 570 :: 1/7/09
|
How can a t test be employed in hypothesis testing by the use of directional versus nondirectional hypothesis. . .
directional test,
1-tailed test |
# 569 :: 12/21/08
|
Faced with rising fax costs, a firm issued a guideline that transmissions of 10 pages or more should be sent by 2-day mail instead. Exceptions are all. . .
1-sample t-test,
TDIST |
# 568 :: 12/21/08
|
16 (a) Plot the data on U.S. general aviation shipments. (b) Describe the pattern and discuss possible causes. (c) Would a fitted trend be helpful? Ex. . .
Trend Line,
Linear Regression |
# 566 :: 12/19/08
|
In an ANOVA test there are 5 observations in each of three treatments. The degrees of freedom in the numerator and denominator respectively are:
a. . . .
ANOVA,
Degrees of Freedom |
# 565 :: 12/19/08
|
The coefficient of correlation between two variables X and Y was computed to be ƒ{0.60. This means
a. the coefficient of determination is 0.
b. a. . .
Correlation,
coefficient of determination |
# 564 :: 12/19/08
|
For each of the following situations, indicate whether an error has occurred and, if so, indicate what kind of error (Type I or Type II) has occurred.. . .
Type I Error,
Type II Error,
Power,
Hypothesis Test |
# 563 :: 12/19/08
|
A vinyl siding company claims that the mean time to install siding on a medium-size house is at most 20 hours with a standard deviation of 3.7 hours. . . .
1-sample Z-test,
1-sample t-test |
# 562 :: 12/17/08
|
Why does the main factor MSs in 2 way ANOVA sometimes carry along interaction effect?. . .
ANOVA,
2-Way ANOVA |
# 560 :: 12/17/08
|
Throughout history 55% of registered voters actually have cast a ballot. What is the probability that among a group of 28 students who are registered. . .
BINOMDIST,
Binomial cdf,
Compliment Rule |
# 559 :: 12/16/08
|
The serum cholesterol levels for men in one age group are normally distributed with a mean of 185.1 and a standard deviation of 37.8. All units are i. . .
Area between,
Z-Score |
# 558 :: 12/16/08
|
If Z is a standard normal variable, find the probability that z lies between 0.73 and 1.88 or P(0.73
Area between,
Z-Score |
# 557 :: 12/16/08
|
Find the margin or error for the 95% confidence interval used to estimate the population proportion. In a survey of 7100 TV viewers, 38% said they wa. . .
Confidence Intervals,
Margin of Error |
# 555 :: 12/14/08
|
Complete the following:
a. Select a variable. Compare the mean of the variable for a sample of 30 for one group with the mean of the variable for a . . .
2-sample t-test,
2-proportion test,
2-sample z-test,
z-test |
# 551 :: 12/12/08
|
Philadelphia is conducting a study on the characteristics of tourists who drive to Eagles football games. Previous studies indicate that approximately. . .
Sample Size,
Confidence Intervals,
Proportion |
# 550 :: 12/12/08
|
Jeff, I am working Trend lines for yearly data and I can't figure this step:
trend line is Tt=22.6+0.45 t to generate yearly forecast. Trend line beg. . .
Trend Line |
# 549 :: 12/10/08
|
An expert witness in a case of alleged racial discrimination in a state university school of nursing introduced a regression of the determinants of Sa. . .
Regression Equation,
Regression Analysis |
# 548 :: 12/10/08
|
A researcher used stepwise regression to create regression models to predict BirthRate (births per 1,000) using five predictors: LifeExp (life expecta. . .
Stepwise Regression,
Regression Analysis |
# 546 :: 12/10/08
|
In the following regression, X = total assets ($ billions), Y = total revenue ($ billions), and n = 64 large banks. (a) Write the fitted regression eq. . .
Regression Analysis,
Slope,
Regression Equation |
# 545 :: 12/10/08
|
In the following regression, X = weekly pay, Y = income tax withheld, and n = 35 McDonald’s employees. (a) Write the fitted regression equation. (b) S. . .
Regression Analysis,
Slope |
# 544 :: 12/10/08
|
(a) How does correlation analysis differ from regression analysis? (b) What does a correlation coefficient reveal? (c) State the quick rule for a sign. . .
Correlation,
correlation coefficient ,
Regression Analysis,
significant correlation |
# 542 :: 12/9/08
|
A financial analyst wants to compare the turnover rates, I percent, for shares of oil-related stocks versus other stocks, such as GE and IBM. She sele. . .
2-sample t-test,
Unequal Variances |
# 541 :: 12/9/08
|
A stockbroker at Critical Securities reported that the mean rate of return on a sample of 10 oil stocks was 12.6 percent with a standard deviation of . . .
F-test,
Homogeneity of Variance,
Unequal Variances,
Levine test |
# 540 :: 12/9/08
|
A sample of 36 observations is selected from a normal population. The sample mean is 21, and the sample standard deviation is 5. Conduct the following. . .
1-sample t-test,
1-tailed test,
Null Hypothesis ,
calculating mean,
sample variance,
Standard Deviation |
# 539 :: 12/9/08
|
The following sample observations were randomly selected
X: 5 3 6 3 4 4 6 8
Y: 13 15 7 12 13 11 9 5
Determine the coefficient of correlati. . .
Correlation,
coefficient of determination |
# 538 :: 12/9/08
|
When would it be appropriate to use ANOVA and when is it appropriate to use a paired t test? Be specific and give examples.. . .
ANOVA,
Paired t-test |
# 537 :: 12/6/08
|
Can people really identify their favorite brand of cola? Volunteers tasted Coca-Cola Classic, Pepsi, Diet Coke, and Diet Pepsi, with the results shown. . .
2-proportion test,
Chi-Square |
# 536 :: 12/6/08
|
High levels of cockpit noise in an aircraft can damage the hearing of pilots who are exposed to this hazard for many hours. A Boeing 727 co-pilot coll. . .
Chi-Square,
CHIDIST |
# 535 :: 12/6/08
|
A student team examined parked cars in four different suburban shopping malls. One hundred vehicles were examined in each location. Research question:. . .
Chi-Square,
CHIDIST |
# 534 :: 12/6/08
|
Sixty-four students in an introductory college economics class were asked how many credits they had earned in college, and how certain they were about. . .
Chi-Square,
CHIDIST |
# 533 :: 12/6/08
|
I need help on understanding multiple logistic regression, especially inference, goodness-of-fit, and calculating Likelihood Ratio Chi-Square using G^. . . |
# 532 :: 12/5/08
|
Based on the genotypes of parents, offspring are expected to have genotypes distributed in such a way that 25% have genotypes denoted by AA, 50% have. . .
Chi-Square,
Goodnees of Fit |
# 531 :: 12/4/08
|
What is higher a z score of .500 or a raw score of 17. . . |
# 530 :: 12/2/08
|
What score would it have taken to be in the 90th percentile in a test with a mean of 40 and standard deviation of 7. . .
Z-Score,
Percent Score |
# 528 :: 11/28/08
|
In a bumper test, three types of autos were deliberately crashed into a barrier at 5 mph, and the resulting damage (in dollars) was estimated. Five te. . .
ANOVA |
# 527 :: 11/28/08
|
A sample of 25 concession stand purchases at the October 22 matinee of Bride of Chucky showed a mean purchase of $5.29 with a standard deviation of $3. . .
Homogeneity of Variance,
F-test,
Levine test |
# 526 :: 11/28/08
|
To test the hypothesis that students who finish an exam first get better grades, Professor Hardtack kept track of the order in which papers were hande. . .
2-sample t-test,
Homogeneity of Variance,
Equal Variances,
F-test,
Levine test |
# 525 :: 11/28/08
|
Does lovastatin (a cholesterol-lowering drug) reduce the risk of heart attack? In a Texas study,
researchers gave lovastatin to 2,325 people and an i. . .
2-proportion test,
Normal Approximation to Binomial |
# 524 :: 11/24/08
|
Discuss how t test can be employed in hypothesis testing by the use of directional vs. nondirectional hypotheses. Discuss types of research where usi. . .
t-score,
Z-Score,
directional test,
nondirectional test,
1-Sided Test |
# 523 :: 11/24/08
|
Use the given degree of confidence and sample data to construct a confidence interval for the population mean x. Assume that the population has a norm. . .
Confidence Intervals,
TINV |
# 521 :: 11/24/08
|
The width of a confidence estimate for a proportion will be:
a. Narrower for a 99% confidence interval than for a 95% confidence interval.
b. Wider . . .
Confidence Level,
Confidence Intervals,
Proportion |
# 520 :: 11/23/08
|
Your company asks you to compare a new advertising campaign and the old one. Sample data on the accounts as follows:
Old: 40, 28, 35, 38, 31, 42, 26,. . .
Confidence Intervals,
Median,
Mode,
mean,
t-statistic,
Standard Error of the Mean |
# 519 :: 11/23/08
|
Fill in the P (X=x) values in the table to give legitimate probability distribution for the discrete random variable X, whose possible values are -4, . . .
Random Variable,
Probability,
Compliment Rule |
# 517 :: 11/22/08
|
An executive drives his vehicle from home to work daily. Driving times are normally distributed with a mean of 35 minutes and standard deviation of 8. . .
Z-Score,
Area between,
above .10 |
# 516 :: 11/19/08
|
Given a mean score of 70, standard deviation of 15,percentile of 23.Find the Z score,T score and raw score.
Please explain how to work backward on a . . .
T score,
Percent Score,
Z-Score |
# 515 :: 11/19/08
|
I run various A/B Split tests online. I always set all my tests for 10,000 visitors so page A and B are each equally rotated 5,000 times. My problem. . .
2-proportion test,
Normal Approximation to Binomial ,
Power,
A/B Testing |
# 514 :: 11/17/08
|
I am trying to assess the impact of an event on a population. I ran a survey before the event and then I ran the survey after the event. The collect. . .
Paired t-test,
Within Subjects,
1-Sided Test,
One-Tailed Test |
# 513 :: 11/17/08
|
I have a question about SEYhat in time-series regression for N=1 subject....
I want to know whether the StdError of the fitted score (SEYhat) can. . .
Time-Series,
Regression Analysis,
autocorrelation |
# 512 :: 11/14/08
|
When estimating the mean of a population, how large must the sample be in order that the 95% error margin is 1/8 the standard deviation?. . .
Sample Size,
Margin of Error,
Standard Deviation,
Standard Error of the Mean |
# 511 :: 11/13/08
|
A machine produces 3 inch nails. A sample of 100 nails is selected, and it is found that 25 are shorter than 3 inches. Find the 95% confidence interv. . .
Proportion,
Confidence Intervals,
One-Tailed Area |
# 510 :: 11/13/08
|
Survey to determine what proportion of new car buyers continue to have their car serviced at the dealership after warranty ends. Estimates 30% of cust. . .
Sample Size,
Confidence Level |
# 509 :: 11/13/08
|
A researcher expects the population proportion of the Cubs Fans in Chicago to be 80%. Error of less than 5% confident of an estimate to be made from a. . .
Confidence Intervals,
Sample Size,
Margin of Error |
# 508 :: 11/13/08
|
In a national wide survey a researcher expects 30 percent of the population will agree with an value statement. He wishes to have less than 2% error a. . .
Sample Size,
Margin of Error,
Confidence Level |
# 507 :: 11/12/08
|
In a survey of 500, 60% responded positively to an value question.
Calculate a confidence level at 95% to get an interval estimate for proportion?. . .
Sample Size,
Confidence Intervals,
Proportion |
# 506 :: 11/12/08
|
Suppose you are planning a sample of employees to determine the monthly average # of vacation days. Standards set: Confidence level of 99% and an erro. . .
Sample Size,
Margin of Error,
Confidence Intervals |
# 505 :: 11/11/08
|
Calculate a 98% confidence interval for the following data 15.7,15.7,15.5,15.2,15.2,15.1,15.3.. . .
Confidence Intervals,
TINV,
Margin of Error,
t-statistic |
# 504 :: 11/9/08
|
Calculate the 95% confidence interval on the following GPA's from 30 randomly selected students.
0.979
0.891
0.962
0.858
0.909
0.936
0.963
0.9. . .
Confidence Intervals,
Margin of Error,
t-statistic |
# 503 :: 11/7/08
|
Choose a variable and collect data for at least three different groups (samples). Compare the means of the three groups using the one-way ANOVA techni. . .
ANOVA,
F-statistic |
# 502 :: 11/7/08
|
Administrative staff based at a business school in the UK are advised to take a 15 minute break from their personal computer after working on it for 9. . .
Confidence Intervals,
TDIST,
t-test,
Z-Score |
# 501 :: 11/7/08
|
In a survey of adults, 68% thought that DNA test for identifying an individual were very reliable. You randomly select 24 adults and ask each if he or. . .
BINOMDIST,
Binomial Probability,
Continuity Correction,
Normal Approximation,
Normal Approximation to Binomial |
# 500 :: 11/7/08
|
In a recent year grade 8 Washington State public school students taking a mathematics assessment test had a mean score of 276.1 with a standard deviat. . .
Percent Score,
Area between,
Z-Score |
# 499 :: 11/7/08
|
A newspaper finds that the mean number of typographical errors per page is five. Find the probability that:
a. Exactly five typographical errors will. . .
Poisson,
Poisson Distribution |
# 498 :: 11/7/08
|
During the next hour, five customer arrivals are expected. What is the probability that more than five customers will show up (according to the Poisso. . .
Poisson,
Poisson Distribution |
# 497 :: 11/6/08
|
A random sample of n=64 children of working mothers showed that they were absent from school an average of 5.3 days per term, with a standard deviatio. . .
Confidence Intervals,
Confidence Level |
# 495 :: 11/4/08
|
The EPA range for a car is 20-28mpg, how large of a sample would be required to estimate your mean mpg with an error of +/- 1 mpg with 90% confidence. . .
Sample Size |
# 494 :: 11/4/08
|
If the average price of a new home is 145,000 what is the minimum and maximum prices of the houses a contractor will need to build to include the midd. . .
Z-Score,
Area between |
# 493 :: 11/4/08
|
On a police sergeants exam, the historical mean scored was 80 with a standard deviation of 20. Four offiers scored 195,175,191, and 189 respectively. . . .
Empirical Rule,
Z-Score,
Unusual Event,
Percent Score |
# 492 :: 11/3/08
 |
if an eligible couple on an average has 3.3 children then the birth rate will be?. . . |
# 491 :: 10/30/08
|
Using continuity Correction. There are many situations in which a normal distribution can be used as a good approximation to a random variable that ha. . .
Continuity Correction |
# 487 :: 10/28/08
|
Find a confidence interval for the mean assuming that each sample is from a normal population. Mean = 127, s = 27, n = 16. Find the 90% Confidence Int. . .
TINV,
t-distribution,
Confidence Intervals |
# 486 :: 10/28/08
|
1.A telescope manufacturer wants its telescopes to have standard deviations in resolution to be significantly below 2 when focusing on objects 500 lig. . . |
# 485 :: 10/27/08
|
Assume that the heights of 5 year old boys are normally distribued with a mean of 100cm and a standard deviation of 60. What is the sampling distribut. . .
TINV,
Confidence Intervals,
Standard Error of the Mean,
Standard Deviation of the Mean |
# 484 :: 10/25/08
|
With a normal distribution of 50 and standard deviation of population =10, how do I figure out the score at the 40th percentile? How do I figure out t. . .
Z-Score,
Area between,
Percent Score |
# 483 :: 10/21/08
|
I have a research study where we have a "test" and a "control" group. We calculated a market share percentage for both groups, the test group was in . . .
McNemar Chi-Square ,
Chi-Square |
# 482 :: 10/20/08
|
a telescpoe manufacturur wants its telescopes to have standard deviations in resolution to be significantly below 2 when focusing on objects 500 light. . . |
# 481 :: 10/20/08
|
a centre university has a student population of 60000. the university is interested in determining what proportion of them is in favour of a new gradi. . . |
# 476 :: 10/13/08
|
Does normal distribution is something to do with Altman Z-Score?. . .
Altman Z-Score,
Z-Score |
# 475 :: 10/12/08
|
A telephone manufacturer wants its telescope to have standard deviation in resolution to be significantly below 2 when focusing on object 500 light-ye. . .
Standard Deviation,
Chi-Square,
Chi-Square Distribution |
# 474 :: 10/12/08
|
The central university has a student population of 60000. The university is interested in determining what proportion of them is in favour of a new gr. . . |
# 471 :: 10/9/08
|
A central university has a student population of 60,000. The university is interested in determining what proportion of them is in favour of a new gra. . .
Margin of Error,
Confidence Intervals,
Sample Size |
# 470 :: 10/9/08
|
A telescope manufacturer wants its telescopes to have standard deviations in resolution to be significantly below 2 when focusing on objects 500 light. . .
Chi-Square Distribution,
Confidence Intervals,
Standard Deviation,
Variance |
# 469 :: 10/8/08
|
Mean output of solar cells of three types are measured six times under random light intensity over a period of 5 minutes, yielding the results shown. . . . |
# 467 :: 10/7/08
|
The Web-based company Oh Baby! Gifts has a goal of processing 95 percent of its orders on the same day they are received. If 485 out of the next 500 o. . .
1-Proportion Test,
Normal Approximation |
# 466 :: 10/7/08
|
Biting an unpopped kernel of popcorn hurts! As an experiment, a self-confessed connoisseur of cheap popcorn counted 773 kernels and put them in a popp. . . |
# 465 :: 10/7/08
|
A sample of 20 pages was taken without replacement from the 1,591-page phone directory Ameritech Pages Plus Yellow Pages On each page, the mean area d. . . |
# 464 :: 10/7/08
|
How do you know when to use a t-score instead of a z-score and vice versa?. . .
Z-Score,
t-score |
# 463 :: 10/6/08
|
Find the probability of correctly answering the first 2 questions on a multiple choice test if random guesses are made and each question has 3 possibl. . .
Multiplication Rule |
# 462 :: 10/6/08
|
Olympic Track related question: You know the last 5 race times at the same distance for 8 runners competing in a race. As such, you can calculate the. . .
Z-Score |
# 461 :: 10/6/08
|
My question is on Measurement system analysis (MSA).
My metric is lead time.
I calculated it from the system (computer database) which stores all th. . .
Gage R&R |
# 460 :: 10/5/08
|
20% kids danced. If 10 were selected at random, find probability that exactly four danced.. . .
BINOMDIST,
Binomial pmf |
# 459 :: 10/5/08
|
How do you calculate a participant score if she was at the 67th percentile? I only have the standard deviation of the population and the mean. s = 27 . . .
Percent Score,
Percentile,
Z-Score |
# 458 :: 10/5/08
|
In 1992, the FAA conducted 86,991 pre-employment drug tests on job applicants who were to be engaged in safety and security-related jobs, and found th. . .
Confidence Intervals,
Normality Assumption |
# 457 :: 10/4/08
|
What is a simple but legitimate power analysis formula? I am trying to do qualitative research on African American HS boys in the Midwest. I am using . . . |
# 456 :: 10/4/08
|
I am trying to find out if a difference between two response sets is significant. I asked 98 boys what modalities they thought were attractive to girl. . .
2-proportion test |
# 455 :: 10/4/08
|
Assume scores are normally distributed with a mean of 10 and std dev of 2. Find the first quartile Q1, which is the score separating the bottom 25% fr. . .
Quartile |
# 454 :: 10/4/08
|
what concerns arise from using formulae to calculate standard scores. . . |
# 453 :: 10/4/08
|
A central university has a student population of 60,000. The university is interested in determining what proportion of them is in favour of a new gra. . .
Sample Size,
Margin of Error |
# 452 :: 10/3/08
|
why does a z score always have a mean of 0 and a standard deviation of 1?. . .
Standard Normal Curve |
# 451 :: 10/3/08
|
A sample of the math test scores of 35 fourth-graders has a mean of 82 with a standard deviation of 15.
Find the 95% confidence interval of the mean. . .
Confidence Intervals,
Confidence Level |
# 450 :: 10/3/08
|
A researcher is interested in estimating the average salary of fire fighters in a large city. He wants to be 95% confident that his estimate is correc. . .
Margin of Error,
Sample Size |
# 447 :: 10/2/08
|
If he correlaion between X and Y is equal to -1.0, what do we know about the prediction of Y by X? (a)It's negative (b) It's postive (c)It's perfect (. . . |
# 446 :: 10/2/08
|
When using two predictor variables, these variables should be (a)Correlated (b)Related (c)Independent (d) Dependent. . . |
# 445 :: 10/2/08
|
What must be used to examine an outcome that is predicted from two independent variables? (a)Multivariate regression (b)Multiple regression (c)Simple . . . |
# 444 :: 10/2/08
|
What mut be done to categorical variables in order to use them in a regression analysis? (a)Nothing (b)Dummy coding (c)Problem coding (d)Categorical c. . . |
# 443 :: 10/2/08
|
A postive trend line is associated with what type of slope? (a)Negative slope (b)Direct slope (c)Postive slope (d)Nondirectional slope. . . |
# 442 :: 10/2/08
|
Using the regression Formula with slope=.704 and intercept=.719, what would the predicted college GPA be for a student whose current high school GPA=3. . . |
# 441 :: 10/2/08
|
Which of the following Excel Function calulated the point at the regression line crosses the y-axis (a)SLOPE (b)CORREL (c)INTERCEPT (d)PEASON. . . |
# 440 :: 10/2/08
|
How would you represent score of Y based on a known value of X? (a)Y (b)y-intercept (c)Y'(d)Y=Xa. . . |
# 439 :: 10/2/08
|
I have a jar containing 100,000 marbles. There are 6 colors of marbles in the jar and they are present at frequencies of 2%, 2%, 4%, 10%, 57%, 25%. . . . |
# 438 :: 10/2/08
|
How do i compute for the standard score (z-score)of the following data? How will the graph look like?
53
53
50
45
45
43
42
42
41
40
39
39
. . . |
# 437 :: 10/1/08
|
how can i interpret standard or z scores?. . . |
# 436 :: 10/1/08
|
when is ecological correlation appropriate?
When is it not useful?. . .
Ecological correlation |
# 435 :: 10/1/08
|
Parametric and Nonparametric Data Identification Assignment
Label each of the following situations “P” if it is an example of parametric data or “NP”. . .
Non-Parametric,
Parametric |
# 433 :: 10/1/08
|
My data set is non-normal (cycle time). Can I convert the data into "Good and Bad" based on a specification and then find a Z value to estimate my sig. . .
Cycle Time,
Non-Normal Data,
Log Transformation |
# 432 :: 9/30/08
|
Assume that the population of heights of male college students is approximately normally distributed with mean m of 68 inches and standard deviation s. . .
TDIST,
t-score |
# 430 :: 9/29/08
|
Individual scores of a placement examination are normally distributed with a mean of 84.2 and a standard deviation of 12.8.
If the score of an indi. . . |
# 429 :: 9/29/08
|
A coin was flipped 60 times and came up heads 38 times. (a) At the .10 level of significance, is the coin biased toward heads? Show your decision rule. . .
Normal Approximation to Binomial ,
1-Proportion Test |
# 428 :: 9/29/08
|
Each student in an experiment was told to look at 100 cars and count the number of people wearing the seat belts. The mean score for the class was fou. . .
Z-Score |
# 427 :: 9/29/08
|
Set up a model to test whether there are differences in mean ... DATA SET E Ages and Weights of 31 Randomly Chosen U.S. Nickels (n = 31 nickels) Nicke. . . |
# 426 :: 9/29/08
|
can individual scores of a 542 student be converted into percentage and fed into spss for anova and tukey test. . .
Percent Score,
ANOVA |
# 425 :: 9/29/08
|
A real estate agent has 2 tours. The first tour through N1and has 10 homes for sale, whereas the second tour through N2and has 5 homes for sale. The r. . . |
