A hardware retailer has average sales of $64,235 with a standard deviation of $5,918 for a 12-month period. The mean monthly sales for all retailers in the chain are $59,844. Is this hardware retailer's sales significantly different from all retailers in the chain at p= .05? Are they significantly different at p= .01? Calculate a .95 confidence interval for the data in problem.
Explain your findings and determine what question the confidence interval answers.
A car dealer is using the number of years customers have owned their vehicles to predict how long it will be before they elect to replace them. The correlation between the two is rxy = -.723 (the longer they have owned their present vehicles, the more quickly they are expected to replace them). The other relevant data are as follows for 32 customers:
How long is the time to expected replacement for a customer who has owned a vehicle 6.5 years?
Calculate .95 and .99 confidence intervals and explain your results.
How will a larger standard deviation in the criterion variable affect the width of the confidence intervals? Why?