SCENARIO 10-6
to Investigate the Efficacy of a Diet, a Random

SCENARIO 10-6
To investigate the efficacy of a diet, a random sample of 16 male patients is selected from a
population of adult males using the diet. The weight of each individual in the sample is taken at the
start of the diet and at a medical follow-up 4 weeks later. Assuming that the population of differences
in weight before versus after the diet follow a normal distribution, the t-test for related samples can be
used to determine if there was a significant decrease in the mean weight during this period. Suppose
the mean decrease in weights over all 16 subjects in the study is 3.0 pounds with the standard
deviation of differences computed as 6.0 pounds.
-Referring to Scenario 10-6, the critical value for a one-tail test of the null hypothesis of no
difference at the $\alpha = 0.05$ level of significance is _______.