In a short essay, define randomization and list and discuss the two types of true experimental design

What will be an ideal response?

Randomization is one method of controlling extraneous variables that involves randomly assigning test units to experimental groups by using random numbers. Treatment conditions are also randomly assigned to experimental groups. Randomization is the preferred procedure for ensuring the prior equality of experimental groups.
a. Pretest-posttest control group design is an experimental design in which the experimental group is exposed to the treatment but the control group is not. Pretest and posttest measures are taken on both groups. Test units are randomly assigned. The randomization of this design controls for most extraneous variables. The extraneous effects are presumed to be equally represented in both the control and experimental groups.
b. Posttest-only control group design is an experimental design in which the experimental group is exposed to the treatment but the control group is not and no pretest measure is taken. Test units are randomly assigned. One significant advantage of this design over the pretest-posttest control is the elimination of the interactive testing effect that comes with pretesting. Additionally, the simplicity of this design offers time, cost, and sample size advantages.