Chapter 10.3, Problem 83E

To determine

To explain why it is not appropriate to perform a paired t test about the true mean difference (Outbound minus Return) in flight times between Dubai and Doha.

Explanation of Solution

To answer the question we must find out if the three conditions are satisfied or not, which is as:

Random: It is satisfied because the samples are independent random samples.

Independent: It is satisfied because the sample of $12$ daysis less than $10\%$ of all population of all days.

Normal: It is not satisfied because the sample is not large and the distribution is not approximately Normal.

Thus, all the conditions are not satisfied since the large sample is not satisfied and it is therefore not appropriate to determine the confidence interval for the population mean difference.