Suppose a 95% confidence interval for the average amount of weight loss on a diet program for males is between 13.0 and 18.0 pounds. These results were based on a sample of 42 male participants who were deemed to be overweight at the start of the 4-month study. What is the margin of error for this study?

The margin of error for this study is 2.5 pounds.

Step-by-step explanation:

The margin of error is the subtraction of the mean by the lower end of the confidence interval, and this must be equal to the subtraction of the upper end to the mean.

In this problem, we have that:

M - 13 = 18 - M

2M = 31

M = 15.5

The mean is 15.5 pounds.

So the margin of error for this study is 15.5 - 13 = 18 - 15.5 = 2.5 pounds.