Question

An automobile manufacturer who wishes to advertise that one of its models achieves 30 mpg (miles per gallon) decides to carry out a fuel efficiency test. Six nonprofessional drivers were selected, and each one drove a car from Phoenix to Los Angeles. The resulting fuel efficiencies (in miles per gallon) are given below.

27.3

29.4

31.2

28.4

30.2

29.6

Assuming that fuel efficiency is normally distributed under these circumstances, do the data contradict the claim that true average fuel efficiency is (at least) 30 mpg? Test the appropriate hypotheses at significance level 0.05. (Use a statistical computer package to calculate the P-value. Round your test statistic to two decimal places and your P-value to three decimal places.)

t=P-value=

State the conclusion in the problem context.

Reject H₀. We have convincing evidence that the mean fuel efficiency under these circumstances is less than 30 miles per gallon.Reject H₀. We do not have convincing evidence that the mean fuel efficiency under these circumstances is less than 30 miles per gallon.    Do not reject H₀. We have convincing evidence that the mean fuel efficiency under these circumstances is less than 30 miles per gallon.Do not reject H₀. We do not have convincing evidence that the mean fuel efficiency under these circumstances is less than 30 miles per gallon.

Answer 1