Exhibit: Department Store.

A random sample of 64 credit sales in a department store showed an average sale of $75.00. From past data, it is known that the standard deviation of the population of sales is $24.00.

(For this exhibit, avoid rounding for the intermediate steps and round your final solutions to 4 decimal places)

1.

Refer to the Exhibit Department Store.

Construct the 96% confidence interval for the population mean and provide the lower bound of the confidence interval below.

2.

Refer to the Exhibit Department Store.

Provide the upperbound of the confidence interval that you calculated above (i.e.96% confidence interval for the population mean).

3.

Refer to the Exhibit Department Store.

Assume that the information about average sales was lost. You decided to repeat the study and collect information for another sample. This time you obtain a random sample of 400 sales which accidentally resulted in the same average sale of $75.00. Construct the 96% confidence interval for the population meanand provide thelowerbound of the confidence interval below.

4.

Refer to the Exhibit Department Store.

Provide theupperbound of the confidence interval that you calculated above (i.e.96% confidence interval for the population mean when you collected new data).

5.

Refer to the Exhibit Department Store.

Compare the intervals constructed for this exhibit. How does an increase in the sample size affect the confidence interval? Explain.