Question: A junior budget analyst in Hopeville, VA thinks that it is time to figure out if the city’s car pool should adopt a single brand for its operations outside of policing, where the Ford Crown Victoria remains standard issue. The analyst thinks that having a single car brand will make repairs easier and allow for standardized modification and procurement, while allowing for lower costs. She thinks that Southwest Airlines approach to jets (they only fly Boeing 737’s) is an example the city should follow.

Currently the city deploys Dodges, Toyotas, and Saturns for its civilian operations. The analyst believes that annual repair costs should be the principal deciding factor on the brand to choose, though she acknowledges that safety, comfort, and other factors should play a role when the city manager weighs in. That said, she wants annual repairs to be the initial variable tested for.

The analyst finds that Total Sums of Squares is (SST) in dollars is $200,000. The Sums of Squares Between (SSG) is 125,000. The analyst has used 12 cars for each brand (n=36).

a) Set up the null and alternative hypotheses

b) Test at 0.05 for equivalence of means

c) What conclusion might the junior budget analyst draw from the findings to pass along to the manager?