Two Group Designs Researches in education and psychology have often been criticized of being loosely controlled. In recent year more rigorous designs have been evolved by using statistics to make researches more scientific more scientific and objective. Generally researchers use two parallel group techniques to seethe effects of an independent variable on some dependent variable. Two group are equated on the basis of significant variable. One group called experimental and the other is called control group. The experimental group is subjected to a certain experience or to a specific treatment whereas the control group is not given any type of special treatment. After providing special treatment to the experimental group, both the groups are administered the same final test. The scores are statistically compared and conclusions are drawn as regards the effect of special treatment on the experimental group. 1. Randomized Control Group Pretest Posttest Design The researcher in this design follows the procedure as given below. i. He selects subject by random method. ii. Assigns subjects to groups and X (Treatment) to groups by random method. iii. Tests the Ss on the dependent variable. iv. Keep all conditions the same for both the groups except for exposing the experimental S but not the control group to the independent variable fora specific time. v. Test the ‘Ss’ on the dependent variable.
20 vi. Finds the difference between the two. vii. Compares the results to see whether the application of X treatment) caused a change in the experimental group. viii. Applies an appropriate statistical procedure.
2. Matched two group design. A matched two group design is a modification of the totally randomized two group design described above. In this design, both groups are matched in terms of some variable, the experimenter feels he would influence the dependent variable. Suppose we want to test the retention of two types of words closely associated and disassociated. We believe that IQ. Will influence how well a person can retain words so we match the two groups on IQ. Let us be more concrete to understand this point. Suppose there are ten subjects with IQ. as follows