The students in Professor Zhao's 50-student Introductory Psychology class were randomly assigned to one of two review sessions, each being taught with a different technique. The next day, every student got all 10 of the test questions correct. What problem does Professor Zhao have in determining the better teaching technique for review sessions?

a. ceiling effect
b. confound acting in reverse
c. attrition
d. instrumentation

A. ceiling effect

Explanation:

The problem Professor Zhao does have in determining the better teaching technique for review sessions is a ceiling effect is known as an effect which occcur at a level where an independent variable no longer has an impact on the dependent variable or has no more effect on a dependent variable.

An example of a ceiling effect is a test which is very easy to solve by those taking it, and this will leads to most of those solving the test to achieve the highest or score close to the highest mark.

So the test has little impact on the dependent variable.