Walmart, Inc has many tractor-trailer trucks. In a sample of 50 trucks, it was found that the
Question:
Walmart, Inc has many tractor-trailer trucks. In a sample of 50 trucks, it was found that the mean weight is 78,500 pounds. It is known that the population standard deviation is 1,700 pounds.
Which distribution (normal or t) should be used for this problem? Explain your response in detail.
Calculate the standard error of the mean.
Construct a 98% confidence interval for the population mean weight of tractor-trailer trucks.
Explain in detail the meaning of the confidence interval created in part “c.”
Suppose the sample of tractor-trailer trucks used in the study was 36. (Compare it to the initial sample of 50) What would happen to the width of the confidence interval? WHY? Explain your response in detail.
Suppose the confidence interval created was a 90% confidence interval.
(Compare it to the initial 98% confidence interval) What would happen to the width of the interval? Explain your response in detail.
Understanding Basic Statistics
ISBN: 9781111827021
6th Edition
Authors: Charles Henry Brase, Corrinne Pellillo Brase