IV.25. Sharks. Great white sharks are big and hungry. Here are the lengths in feet of 44 great whites:
| 18.7 | 12.3 | 18.6 | 16.4 | 15.7 | 18.3 | 14.6 | 15.8 | 14.9 | 17.6 | 12.1 |
| 16.4 | 16.7 | 17.8 | 16.2 | 12.6 | 17.8 | 13.8 | 12.2 | 15.2 | 14.7 | 12.4 |
| 13.2 | 15.8 | 14.3 | 16.6 | 9.4 | 18.2 | 13.2 | 13.6 | 15.3 | 16.1 | 13.5 |
| 19.1 | 16.2 | 22.8 | 16.8 | 13.6 | 13.2 | 15.7 | 19.7 | 18.7 | 13.2 | 16.8 |
(a) Make a stemplot with feet as the stems and 10ths of feet as the leaves. There are two outliers, one in each direction. These won’t change much but will increase the standard deviation s. (Hint: See pages 253–255.)
(b) Give a 90% confidence interval for the mean length of all great white sharks. (The interval may be too wide due to the influence of the outliers on s.) (Hint: See pages 508–509.)
(c) What do we need to know about these sharks in order to interpret your result in part (b)? (Hint: See pages 508–509.)