Question

The manufacturers of a dietary supplement claim that their product will help customers lose weight. To test their claim, they select a sample of nine subjects, and their weights are recorded. Then, the ten subjects take the supplement for one month, and their weights are recorded again. The weights, before and after, are listed below: Subject 1 2 3 4 5 6 7 8 9 Before 225 245 188 210 282 275 230 195 190 After 215 240 188 212 175 260 225 200 185 Assuming that this data is used to conduct a hypothesis test to test the manufaturers' claim, what would be the test statistic

Answer 1

Assuming that this data is used to conduct a hypothesis test to test the manufacturers' claim, the test statistic we an use is:

the paired sample t-test.

Explanation:

a) Data and Analysis:

Subject Before After

1 225 215

2 245 240

3 188 188

4 210 212

5 282 175

6 275 260

7 230 225

8 195 200

9 190 185

b) The paired sample t-test is used to compare the means from the same dataset but at different times (say, one month apart). It supports the comparison of sample data before and after the data subjects have taken the dietary supplement. When the t-value is high, it is an evidence that the null hypothesis should be rejected. The higher value of the t-test, therefore, indicates that there is a large difference between the two sample sets. On the other hand, a small t-value shows similarity between the two sample sets.