Randomly selected 15 student cars have ages with a mean of 8 years and a standard deviation of 3.4 years, while randomly selected 28 faculty cars have ages with a mean of 5.7 years and a standard deviation of 3.3 years.
1. Use a 0.01 significance level to test the claim that student cars are older than faculty cars.
(a) The test statistic is 2.136
(b) The critical value is 2.624
2. Construct a 99% confidence interval estimate of the difference μs−μf, where μs is the mean age of student cars and μf is the mean age of faculty cars.
? <(μs−μf)< ?
