Question

pretest posttest.Explain

Answer 1

""" A type of true experimental design where test units are randomly allocated to an experimental group and a control group. Both groups are measured before and after the experimental group is exposed to a treatment. ""

A pretest posttest design is an experiment where measurements are taken both before and after a treatment. The design means that you are able to see the effects of some type of treatment on a group. Pretest posttest designs may be quasi-experimental, which means that participants are not assigned randomly.

You've probably got some ideas of how experiments should be run. Why don't researchers just look at something, poke it with a stick, and then study the changes? Researchers are always making things super complicated.

I am glad to inform you that there is a methodology very similar to this, most of the time occurring without the stick. A pretest-posttest design is usually a quasi-experiment where participants are studied before and after the experimental manipulation. Remember, quasi-experimental simply means participants are not randomly assigned. It is possible to have a control group, or a group who doesn't receive the manipulation, but we will not be looking at that in this lesson. In a pretest-posttest design, there is only one group and all of them are in the experimental condition.

Pretest Posttest Design.

The pre-test post-test control group design is also called the classic controlled experimental design. The design includes both a control and a treatment group. For example, if you wanted to gauge if a new way of teaching math was effective, you could:

• Randomly assign participants to a treatment group or a control group.
• Administer a pre-test to the treatment group and the control group.
• Use the new teaching method on the treatment group and the standard method on the control group, ensuring that the method of treatment is the only condition that is different.
• Administer a post-test to both groups.
• Assess the differences between groups.

Two issues can affect the Randomized Control-Group Pretest Posttest Design:

• Internal validity issues: maturation (i.e. biological changes in participants can affect differences between pre- and post-tests) and history (where participants experience something outside of the treatment that can affect scores).
• External validity issues: Interaction of the pre-test and the treatment can occur if participants are influenced by the tone or content of the question. For example, a question about how many hours a student spends on homework might prompt the student to spend more time on homework.

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