Confidence Intervals.
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 ? Are they significantly different at ? Calculate a .95 confidence interval for the data in problem.
Explain your findings and determine what question the confidence interval answers.
Guided Response: Review several of your classmates’ postings. Respond to at least two classmates by commenting on whether or not you think changing the confidence intervals will result in a different outcome. Explain if you agree or not with the role of a confidence interval in the interpretation of the answer
Correlation and Confidence Intervals.
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 (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:
Based on the information above, answer the following questions:
a. How long is the time to expected replacement for a customer who has owned a vehicle 6.5 years?
b. Calculate .95 and .99 confidence intervals and explain your results.
c. How will a larger standard deviation in the criterion variable affect the width of the confidence intervals? Why?
