Which is a critical difference between quasi-experimental and experimental designs?

a. experimental designs randomly assign subjects to different treatment conditions.

b. experimental designs use pre-existing life events as treatments.

c. quasi-experiments are lower in external validity than experiments.

d. quasi-experiments are lower in imposition of units than experiments.

experimental designs randomly assign subjects to different treatment conditions

Explanation:

In experimental design, participants are put into different groups with unique test conditions. In Quasi-experimental design, groups are selected without any random pre-selction actions. The major difference between these types of designs is that in experiment designs, subjects are randomly assigned to different treatment conditions.