Question

# Thirty randomly selected student cars have ages with a mean of 7.8years and a standard deviation...

Thirty randomly selected student cars have ages with a mean of 7.8years and a standard deviation of 3.4 years, while fifteen randomly selected faculty cars have ages with a mean of 5.2 years and a standard deviation of 3.7 years.

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

(a) State the null and alternative hypotheses. (Type mu1 for the population mean age of student cars, and mu2 for the population mean age of faculty cars.)
H0 :
H1 :

(b) Find the rejection region.
Reject H0 if t>

(c) Find the test statistic. (Round your final answer to 2 decimal places.)
t =

(d) Do these samples provide significant evidence that student cars are older than faculty cars, on average? (Type: Yes or No )

2. Construct a 99% confidence interval estimate of the difference μ1−μ2, where μ1 is the mean age of student cars and μ2 is the mean age of faculty cars. (Round your final answer to 2 decimal places.)
(  ,  )

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