Twenty people participate in a weight-loss program for 2 months.Their weights after the 2 months are compared to their starting weights.What kind of mean difference might be expected if the null hypothesis is true for a paired-samples t test?
A) a loss of pounds, on average, showing the effectiveness of the program
B) a negative mean difference, indicating significant weight loss
C) no change in weight or weight gain, indicating that the program does not work
D) weight loss, indicating that the program does not work

Question

Quizplus · Accepted Answer

If the null hypothesis is true, there should be no significant difference between the participants' weights before and after the program. Therefore, no change in weight or weight gain would be expected, indicating that the program does not work. A or B would only be expected if the alternative hypothesis is true, while D contradicts the statement that weight loss is expected.

Twenty People Participate in a Weight-Loss Program for 2 Months