Statistical (experimental research) designs

These are the more advanced experimental research designs than the basic and true
experimental designs. Statistical designs consist of a series of basic experiments that allow for statistical control and analysis of external variables. In other words, several basic experiments are conducted simultaneously. Statistical designs offer many advantages.

These are:
(1) The effect of more than one independent variable can be measures on dependent variable, (2) Specific extraneous variable can be statistically controlled, and (3) Economic designs can be formulated when each test unit is measured more than once.