Question

At a school there are two different math classes of the same age. The two classes have different teachers. The school principle is interested in gauging the effectiveness of two different teaching methods and asks each teacher to try one of the methods. At the end of the semester both classes are given the same test and the results are compared.

a. Is this an experiment or an observational study?​​​​​

b. What is the variable of interest?​​​​​​​

c. Give some examples of variables which could be confounding variables.​​

Answer 1

a) The main difference between observational study and experimental study is in the way the observation is done. In an experiment, the researcher will undertake some experiment and not just make observations. In observational study, the researcher simply makes an observation and arrives at a conclusion.

This is an experimental study. Because the principle assigned one method (to be tested) to each teacher.

b) The variable of interest are the scores obtained (results) by the students in the test at the end of semester. Scores will tell the effectiveness of the method.

c) Prior knowledge in maths of the students may affect the final results.

Teacher's efficiency in teaching will affect results.

No. of hours the student studies for the test will have an effect on the results.

Grasping power (intelligence) of the students will have an effect.