試題詳解

15. The manufacturet of an over-the-counter pain reliever claims that its product brings pain relief to headache sufferers in less than 3.5 minutes, on average. To be ablc to make this claim in its television advertisements, the manufacturer was required to present statistical evidence in support of their claim. The manufacturer reported that for a random sample of 50 headache sufferers, the mean time to relief was 3.3 minutes and the standard deviation was 60 seconds. Find the rejection region for the test if testing at a= .05.
(A)Reject H₀ ifz＜-1.96.
(B) Reject  H₀ ifz＜-1.645.
(C)Reject  H₀ ifz＜-1.282.
(D)Reject H₀ ifz ＜ -1.96 or z ＞1.96.