Jobs and productivity! How do retail stores rate? One way toanswer this question is to examine annual profits per employee. Thefollowing data give annual profits per employee (in units of 1thousand dollars per employee) for companies in retail sales.Assume σ ≈ 3.9 thousand dollars.

3.6	6.6	3.5	8.9	8.4	5.7	8.1	6.5	2.6	2.9	8.1	−1.9
11.9	8.2	6.4	4.7	5.5	4.8	3.0	4.3	−6.0	1.5	2.9	4.8
−1.7	9.4	5.5	5.8	4.7	6.2	15.0	4.1	3.7	5.1	4.2

(a) Use a calculator or appropriate computer software to findx for the preceding data. (Round your answer to twodecimal places.)
thousand dollars per employee

(b) Let us say that the preceding data are representative of theentire sector of retail sales companies. Find an 80% confidenceinterval for μ, the average annual profit per employee forretail sales. (Round your answers to two decimal places.)

lower limit   Â	thousand dollars
upper limit   Â	thousand dollars

(c) Let us say that you are the manager of a retail store with alarge number of employees. Suppose the annual profits are less than3 thousand dollars per employee. Do you think this might be lowcompared with other retail stores? Explain by referring to theconfidence interval you computed in part (b).

Yes. This confidence interval suggests that the profits peremployee are less than those of other retail stores.No. Thisconfidence interval suggests that the profits per employee do notdiffer from those of other retailstores.    

(d) Suppose the annual profits are more than 6.5 thousand dollarsper employee. As store manager, would you feel somewhat better?Explain by referring to the confidence interval you computed inpart (b).

Yes. This confidence interval suggests that the profits peremployee are greater than those of other retail stores.No. Thisconfidence interval suggests that the profits per employee do notdiffer from those of other retailstores.    

(e) Find an 95% confidence interval for μ, the averageannual profit per employee for retail sales. (Round your answers totwo decimal places.)

lower limit   Â	thousand dollars
upper limit   Â	thousand dollars

Let us say that you are the manager of a retail store with a largenumber of employees. Suppose the annual profits are less than 3thousand dollars per employee. Do you think this might be lowcompared with other retail stores? Explain by referring to theconfidence interval you computed in part (b).

Yes. This confidence interval suggests that the profits peremployee are less than those of other retail stores.No. Thisconfidence interval suggests that the profits per employee do notdiffer from those of other retailstores.    

Suppose the annual profits are more than 6.5 thousand dollars peremployee. As store manager, would you feel somewhat better? Explainby referring to the confidence interval you computed in part(b).

Yes. This confidence interval suggests that the profits peremployee are greater than those of other retail stores.No. Thisconfidence interval suggests that the profits per employee do notdiffer from those of other retail stores.