Questions: To help assess student learning in her developmental science courses, a science professor at a university implemented pre- and post-tests for her developmental science students. A knowledge-gained score was obtained by taking the difference of the two test scores. What type of experimental design is this? Completely randomized design Matched pair Randomized block design Case-control What is the response variable in this experiment? Difference in test scores Total in test scores The score on the posttest The score on the pretest What is the treatment? Background of student Science course Science scores Type of school

The answer is:

1. Matched pair: The experimental design described involves comparing the same students' performance before and after the intervention (the developmental science course). This is characteristic of a matched pair design, where each subject serves as their own control.

Explanation for each option:

• Completely randomized design: This design randomly assigns subjects to different groups without considering any matching or pairing. It does not fit the scenario where the same students are tested before and after the course.
• Matched pair: Correct. This design involves pairing subjects based on certain criteria, or in this case, using the same subjects for both pre- and post-tests.
• Randomized block design: This design involves grouping subjects into blocks based on certain characteristics before randomly assigning treatments within each block. It is not applicable here since the same students are tested twice.
• Case-control: This design compares subjects with a condition (cases) to those without (controls). It is not relevant to the pre- and post-test scenario described.

2. The response variable in this experiment is: Difference in test scores: The response variable is the outcome that is measured to assess the effect of the treatment. In this case, it is the difference between the pre-test and post-test scores, which indicates the knowledge gained.

Explanation for each option:

• Difference in test scores: Correct. This is the measure of the effect of the developmental science course.
• Total in test scores: This is not relevant as the focus is on the change in scores, not the total.
• The score on the posttest: This alone does not capture the change or improvement due to the course.
• The score on the pretest: This alone does not capture the change or improvement due to the course.

3. The treatment in this experiment is: Science course: The treatment is the intervention or condition applied to the subjects. In this case, it is the developmental science course that the students are taking.

Explanation for each option:

• Background of student: This is not the treatment; it could be a variable of interest but not the intervention.
• Science course: Correct. This is the intervention being tested to see its effect on students' knowledge.
• Science scores: These are the outcomes measured, not the treatment.
• Type of school: This is not relevant to the treatment being applied in this experiment.