In: Statistics and Probability
using excel>addin>phstat>confidence interval
we have
Confidence Interval Estimate for the Mean | |
Data | |
Population Standard Deviation | 9.4 |
Sample Mean | 34.73333333 |
Sample Size | 42 |
Confidence Level | 75% |
Intermediate Calculations | |
Standard Error of the Mean | 1.4505 |
Z Value | -1.1503 |
Interval Half Width | 1.6685 |
Confidence Interval | |
Interval Lower Limit | 33.06 |
Interval Upper Limit | 36.40 |
1. sample mean for the preceding data.
34.73 thousand dollars
2. 75% confidence interval for μ
(a) lower limit = 33.06 thousand dollars
(b) upper limit = 36.40 thousand dollars
3.
(c) No. This confidence interval suggests that the bank profits are less than those of other financial institutions.
4. 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 (2).
(a) No. This confidence interval suggests that the bank profits are higher than those of other financial institutions.
Confidence Interval Estimate for the Mean | |
Data | |
Population Standard Deviation | 9.4 |
Sample Mean | 34.73333333 |
Sample Size | 42 |
Confidence Level | 90% |
Intermediate Calculations | |
Standard Error of the Mean | 1.4505 |
Z Value | -1.6449 |
Interval Half Width | 2.3858 |
Confidence Interval | |
Interval Lower Limit | 32.35 |
Interval Upper Limit | 37.12 |
5. Find a 90% confidence interval for μ, the average annual profit per employee for all successful banks. (Round your answers to two decimal places.)
(a) lower limit = 32.35 thousand dollars
(b) upper limit = 37.12 thousand dollars
(6. Let us say that you are the manager of a local bank with a large number of employees. Suppose the annual profits per employee are less than 30 thousand dollars per employee. Do you think this might be somewhat low compared with other successful financial institutions? Explain by referring to the confidence interval you computed in part (5).
(c) No. This confidence interval suggests that the bank profits are less than those of other financial institutions.
7. 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 5.
(a) No. This confidence interval suggests that the bank profits are higher than those of other financial institutions.