Question

A school psychologist wants to test the effectiveness of a new method of teaching logic. She recruits 200 sixth​-grade students and randomly divides them into two groups. Group 1 is taught by means of the new​ method, while group 2 is taught by traditional methods. The same teacher is assigned to teach both groups. At the end of the​ year, an achievement test​ (graded on a scale from​ 1-10) is administered and the results of the two groups are compared. Complete parts​ (A) through​ (D) below.

A. What is the response variable in this experiment?

a. The score on the achievement test.
b. The students' ability in Health.
c. The score of Group 2 on the achievement test.
d. The score of Group 1 on the achievement test.

B. Which of the following explanatory variables is manipulated?

a. Intelligence
b. Teacher
c. Method of teaching
d. Grade level

C. How many levels of the treatment are there?

D. What type of experimental design is this?

a. Survey
b. Randomized block design
c. Completely randomized assignment
d. Matched Pair

Answer 1

In a statistical experiment, a response variable is something that “responds” to the changes made in the experiment. The changes are made to the independent variable (also called the manipulated variable).

For the experiment in question:

The response variable is the score on the achievement test.

The explanatory variable that is manipulated is the method of teaching

There are two levels of treatment ( the new teaching method and the traditional treating method)

The type of experimental design used is: Completely randomized assignment