Mr. Jacobs wants to find out whether a new program for teaching physical education promotes students’ physical development. He gives his students a number of tests before they begin the program (pretests) and the same tests again after they have been in the program for eight months (posttests). He finds that the students’ posttest scores are higher than their pretest scores and so concludes that the program is effective. What is definitely wrong with Mr. Jacobs’ conclusion? a. Eight months is too short a time for such a program to have a long-term effect. b. There are other possible explanations for his results. c. Tests are not a good measure of physical development. d. The posttests should always be different from the pretests

The correct option is letter B. There are other possible explanations for his results.

Explanation:

One possible explanation for the results, for instance, is the fact that all the students have already taken the same tests before. It is okay to use the same tests again but, since students already know it, they could figure out a way to do better this time. For Mr. Jacobs to be sure of his results, he should have divided his students into two groups. One group would train according to the new program and the other group wouldn't. They would be tested and have their results compared. If the experimental group - the one that used the new program - did better than the control group, then Mr. Jacobs could conclude the program works.

b) to encourage free trade

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