Experimental research is useful when the researcher has a particular hypothesis or research question regarding a causal link between two variables. It is ethical, feasible and possible to do manipulation of independent variables. It assigns participants randomly to the situations. The researcher manipulates one variable and randomizes or controls the rest of the variables. It has a control group. The subjects are assigned randomly to groups. The researcher tests only one effect at a time. Randomization is a method of sampling used in experiments for scientific purposes. It is used to obtain results that are unbiased with regard to the impact of treatment,