Question

Randomly selected 24 student cars have ages with a mean of 8 years and a standard deviation of 3.6 years, while randomly selected 30 faculty cars have ages with a mean of 6 years and a standard deviation of 3.3 ears.

1. Use a 0.01 significance level to test the claim that student cars are older than faculty cars.

(a) The test statistic is ___________

(b) The critical value is ___________

(c) Is there sufficient evidence to support the claim that student cars are older than faculty cars?

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)< : _________

Answer 1

Let denote the age of student cars and faculty cars respectively.

1.

2.