In research on cell phone use by teenagers it was found that the average time for a call was at least 15 minutes. Social psychologists feel that this study understated the time. To determine this claim, cell phone bills for 15 teenagers were evaluated. On average, the time spent was 18.5 minutes per call with a sample standard deviation of four minutes (assume a normal distribution) .
-How would you define the rejection region for this test at ? = .001?

Question

In research on cell phone use by teenagers it was found that the average time for a call was at least 15 minutes. Social psychologists feel that this study understated the time. To determine this claim, cell phone bills for 15 teenagers were evaluated. On average, the time spent was 18.5 minutes per call with a sample standard deviation of four minutes (assume a normal distribution).
-How would you define the rejection region for this test at ? = .001?
A)t > 1.711
B)t > 2.33
C)t > 2.492
D)t > 3.646 and t < -3.646
E)t > 3.787

Quizplus · Accepted Answer

The rejection region for a one-tailed t-test at a significance level of 0.001 with 14 degrees of freedom (n-1 = 15-1) is t > 3.787.

In Research on Cell Phone Use by Teenagers It Was