Chapter 6.2, Problem 6.14ACB

Wear-out of used display panels. Refer to Exercise 4.12 (p. 246) and the study of the wear-out failure time of used colored display panels purchased by an outlet store. Recall that prior to acquisition, the panels had been used for about one-third of their expected lifetimes. The failure times (in years) for a sample of 50 used panels are reproduced in the table. An SPSS printout of the analysis is shown below.

1. a. Locate a 95% confidence interval for the true mean failure time of used colored display panels on the printout.
2. b. Give a practical interpretation of the interval, part a.
3. c. In repeated sampling of the population of used colored display panels, where a 95% confidence interval for the mean failure time is computed for each sample, what proportion of all the confidence intervals generated will capture the true mean failure time?