The experimental research has two major characteristics. First, it attempts to influence a certain variable; specifically, it manipulates the independent variable. Second, an experimental research tests hypotheses about cause-and-effect relationships. At the same time, experimental research has three types of designs, these are (1) Two Group Posttest-Only Design; (2) Two-Group Pretest-Treatment-Posttest Design; and (3) Matched Control Group Design.
The two-group posttest-only design. It consists of two groups, a control, and an experimental group. Randomly, the participants are assigned to either the control or experimental group while the treatment (the independent variable) is only given to the treatment group. Thus, both the control and experimental groups (dependent variable) are subsequently tested.
The two-group pretest-treatment-posttest design. It is regarded as a strong experimental design for two reasons. Firstly, the design consists of the usage of both a control and treatment group. Secondly, the design requires a pretest and posttest are directed to both the control and treatment group. This type of design serves to guarantee that the respective participants in both groups are equivalent as possible on the particular variables before the implementation of the treatment for the treatment group.
The matched control group design. It requires researchers to match participants before assigning them to either the control or treatment group. After the participants are randomly selected from a population, they are rank ordered considering the specific variable that is closely related to the posttest measure. Then, the participants are paired in accordance to the rankings.
Works Cited
"Characteristics of Experimental Research." 22 September 2015. 1-14. Web. 28 April 2016.
<https://www.aea267.k12.ia.us/system/assets/uploads/files/1468/experimental_research_9.22.15.pdf>.
