1-Television viewers often express doubts about the validity ofcertain commercials. In an attempt to answer their critics, a largeadvertiser wants to estimate the true proportion of consumers whobelieve what is shown in commercials. Preliminary studies indicatethat about 40% of those surveyed believe what is shown incommercials. What is the minimum number of consumers that should besampled by the advertiser to be 95% confident that their estimatewill fall within 2% of the true population proportion?
2- An auditor for a hardware store chain wished to compare theefficiency of two different auditing techniques. To do this heselected a sample of nine store accounts and applied auditingtechniques A and B to each of the nine accounts selected. Thenumber of errors found in each of techniques A and B is listed inthe table below:
| Errors in A | Errors in B |
| 25 | 11 |
| 28 | 17 |
| 26 | 19 |
| 28 | 17 |
| 32 | 34 |
| 30 | 25 |
| 29 | 29 |
| 20 | 21 |
| 25 | 30 |
Select a 90% confidence interval for the true mean difference inthe two techniques.
a) [0.261, 8.627]
b) [-4.183, 4.183]
c) [2.195, 6.693]
d) [3.050, 5.838]
e) [2.584, 6.304]
f) None of the above
