An experimental design is a systematic process that allows researchers to evaluate the relationship between dependent and independent variables. There are three widely used types of experimental design - pre-experimental design, true experimental design, and quasi-experimental design. In pre-experimental design, the researcher compares the data before and after some interventions or treatments. The true-experimental design has more than one purposefully created group, a commonly measured outcome, and a random assignment. Here, subjects are divided into control and test groups. The control is maintained throughout the experiment without any treatment. The data from test group is then compared with control group to understand the baseline response and validate the treatment. The Quasi-experimental design is typically used in cases where random assignment is impractical.