In a short essay, describe the four broad categories of experimental designs and discuss the various applications of each design category

What will be an ideal response?

a. Preexperimental designs are designs that do not use randomization to control for extraneous factors. Thus, they suffer from many threats to internal and external validity. However, with a proper note of their limitations, they can add value when used in an exploratory fashion.
b. True experimental designs are designs in which the researcher can randomly assign subjects and experimental groups. Therefore, these designs provide a larger degree of control over extraneous variables. Included in this category are the pretest-posttest control group design and the posttest-only control group design.
c. Quasi-experimental designs are designs that result when the researcher is unable to fully manipulate the independent variables or treatments but can still apply part of the apparatus of true experimentation. These designs are typically employed in natural environments, enabling some degree of experimental control in a natural setting.
d. Statistical designs are series of basic experiments that allow for statistical control and analysis of external variables. Statistical designs are classified on the basis of their characteristics and use. The important statistical designs include factorial designs.