Chapter 8.2, Problem 8.12ACB

Lobster trap placement. Refer to the Bulletin of Marine Science (April 2010) study of lobster trap placement. Exercise 6.29 (p. 324). Recall that the variable of interest was the average distance separating traps—called trapspacing— deployed by teams of fishermen. The trap-spacing measurements (in meters) for a sample of seven teams from the Bahia Tortugas (BT) fishing cooperative are repeated in the table. In addition, trap-spacing measurements for eight teams from the Punta Abreojos (PA) fishing cooperative are listed. For this problem, we are interested in comparing the mean trap-spacing measurements of the two fishing cooperatives.

1. a. Identify the target parameter for this study.
2. b. Compute a point estimate of the target parameter.
3. c. What is the problem with using the normal (z) statistic to find a confidence interval for the target parameter?
4. d. Find a 90% confidence interval for the target parameter.
5. e. Use the interval, part d, to make a statement about the difference in mean trap-spacing measurements of the two fishing cooperatives.
6. f. What conditions must be satisfied for the inference, part e, to be valid?