View Answered Questions
No. & Date Asked  Question 

# 283 :: 7/19/08

The lengths of pregnancies are normally distributed with a mean of 264 days and a standard deviation of 25 days. If 100 women are randomly selected, f. . .
ZScore,
Area between 
# 318 :: 8/6/08

A traffic study at one point on an interstate highway shows that vehicle speeds are normally distributed with a mean of 61.3 mph and a standard deviat. . .
Area between,
ZScore 
# 321 :: 8/7/08

A normal distributed population has a mean of 250 pounds and a standard deviation of 10 pounds. Given n = 20, what is the probability that this sample. . .
Area between 
# 356 :: 8/24/08

The mean weight of 500 students is 151 lbs and the standard deviation is 15 lbs. Assuming the weights are normally distributed, find out how many stu. . .
Area between,
ZScore 
# 367 :: 9/5/08

find the area under standard normal curve which lies (a) to the right of Z=1.76,(b)to the left of Z=.94,(c)to the right of Z=.65,(d)b/w Z=.34 & Z=.62. . .
Area between,
ZScore 
# 370 :: 9/6/08

The accounting department at Weston reports that it takes two construction workers a mean of 32 hours and a standard deviation of 2 hours... Determin. . .
Area between,
ZScore 
# 390 :: 9/18/08

How do you find the normal distribution when the mean is 50 witha standard deviation between scores of 32 and 47?. . .
Area between,
ZScore 
# 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. . .
ZScore,
Area between,
Percent Score 
# 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. . .
ZScore,
Area between 
# 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,
ZScore 
# 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. . .
ZScore,
Area between,
above .10 
# 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,
ZScore 
# 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,
ZScore 
# 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. . .
ZScore,
Area between 
# 794 :: 8/10/09

A psychologist has developed a test to measure selfcontrol. The test is normed so that it has a mean of 100 and a standard deviation of 15... The s. . .
ZScore,
Percent Score,
Percentile Rank,
Area between 
# 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. . .
ZScore,
Area between 
# 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,
ZScore 
# 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. . .
ZScore,
Area between,
Standard Error of the Mean 