Question

A survey of 15 large U.S. Massachusetts cities finds that the average commute time one way is 30 minutes. An executive feels that the commute in his city is less and wants to publicize this. He randomly selects 27 commuters and finds the average is 25.1 minutes with a standard deviation of 5.4 minutes. At a α = 0.10, is he correct?

Answer 1

given data are:-

sample size (n) = 27

sample mean () = 25.1

sample standard deviation (s) = 5.4

hypothesis:-

[ this is the executive's claim ]

the test statistic is:-

degrees of freedom = (n-1) = (27-1) = 26

p value is :-

[ in any blank cell of excel type =T.DIST(-4.715,26,TRUE)]

decision:-

p value = 0.0000 < 0.10 (alpha)

so, we reject the null hypothesis.

conclusion:-

there is sufficient evidence to support the executive's claim.In other words, we can say that he is correct.

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