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8 Questions returned
No. & Date AskedQuestion
# 913 :: 12/5/11
Question 913 has been Answered
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

# 824 :: 11/8/09
Question 824 has been Answered
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

# 520 :: 11/23/08
Question 520 has been Answered
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

# 512 :: 11/14/08
Question 512 has been Answered
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

# 485 :: 10/27/08
Question 485 has been Answered
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

# 391 :: 9/18/08
Question 391 has been Answered
An engineer in an automotive factory wishes to know what the tire pressure is on all cars leaving the factory. She measures the tire pressure on a sa. . .

Standard Error of the Mean, t-statistic, Confidence Intervals, Critical Value

# 315 :: 8/5/08
Question 315 has been Answered
An engineer in an automotive factory wishes to know what the tire pressure is on all cars leaving the factory. She measures the tire pressure on a sa. . .

Standard Error of the Mean, Standard Deviation, Confidence Intervals, Critical Value, t-statistic

# 151 :: 4/14/08
Question 151 has been Answered
A random sample of 25 households finds that an average of 2.3 people reside in each house (the standard deviation is 0.35). With a 95% confidence lev. . .

TINV, t-statistic, t-distribution, Confidence Intervals, Standard Error of the Mean, Margin of Error