The price of a share of stock divided by the company's estimatedfuture earnings per share is called the P/E ratio. High P/E ratiosusually indicate "growth" stocks, or maybe stocks that are simplyoverpriced. Low P/E ratios indicate "value" stocks or bargainstocks. A random sample of 51 of the largest companies in theUnited States gave the following P/E ratios†.
| 11 | 35 | 19 | 13 | 15 | 21 | 40 | 18 | 60 | 72 | 9 | 20 |
| 29 | 53 | 16 | 26 | 21 | 14 | 21 | 27 | 10 | 12 | 47 | 14 |
| 33 | 14 | 18 | 17 | 20 | 19 | 13 | 25 | 23 | 27 | 5 | 16 |
| 8 | 49 | 44 | 20 | 27 | 8 | 19 | 12 | 31 | 67 | 51 | 26 |
| 19 | 18 | 32 |
(a) Use a calculator with mean and sample standard deviationkeys to find the sample mean x and sample standard deviations. (Round your answers to one decimal place.)
(b) Find a 90% confidence interval for the P/E population mean ? ofall large U.S. companies. (Round your answers to one decimalplace.)
(c) Find a 99% confidence interval for the P/E population mean ? ofall large U.S. companies. (Round your answers to one decimalplace.)
