Jobs and productivity! How do banks rate? One way to answer this question is to examine annual profits per employee. The following is data about annual profits per employee (in units of 1 thousand...

Jobs and productivity! How do banks rate? One way to answer this question is to examine annual profits per employee. The following is data about annual profits per employee (in units of 1 thousand dollars per employee) for representative companies in financial services. Assume ? ≈ 9.2 thousand dollars.
42.5 29.2 41.8 26.4 29.9 34.8 43.2 50.9 42.5 33.0 33.6
36.9 27.0 47.1 33.8 28.1 28.5 29.1 36.5 36.1 26.9 27.8
28.8 29.3 31.5 31.7 31.1 38.0 32.0 31.7 32.9 23.1 54.9
43.8 36.9 31.9 25.5 23.2 29.8 22.3 26.5 26.7

(b) Let us say that the preceding data are representative of the entire sector of (successful) financial services corporations. Find a 75% confidence interval for ?, the average annual profit per employee for all successful banks. (Round your answers to two decimal places.)
lower limit ___________ thousand dollars
upper limit ____________ thousand dollars

(d) Suppose the annual profits are more than 40 thousand dollars per employee. As manager of the bank, would you feel somewhat better? Explain by referring to the confidence interval you computed in part (b).
A. No. This confidence interval suggests that the bank profits are higher than those of other financial institutions.
B. No. This confidence interval suggests that the bank profits do not differ from those of other financial institutions.
C. Yes. This confidence interval suggests that the bank profits are higher than those of other financial institutions.
D. Yes. This confidence interval suggests that the bank profits do not differ from those of other financial institutions.

(e) Find a 90% confidence interval for ?, the average annual profit per employee for all successful banks. (Round your answers to two decimal places.)
lower limit _____________ thousand dollars
upper limit ______________ thousand dollars

Extracted text: Jobs and productivity! How do banks rate? One way to answer this question is to examine annual profits per employee. The following is data about annual profits per employee (in units of 1 thousand dollars per employee) for representative companies in financial services. Assume o x 9.2 thousand dollars. 42.5 29.2 41.8 26.4 29.9 34.8 43.2 50.9 42.5 33.0 33.6 36.9 27.0 47.1 33.8 28.1 28.5 29.1 36.5 36.1 26.9 27.8 28.8 29.3 31.5 31.7 31.1 38.0 32.0 31.7 32.9 23.1 54.9 43.8 36.9 31.9 25.5 23.2 29.8 22.3 26.5 26.7