Factorial Experiment

In the experimental designs that we have considered up to this point we have been interested in the effects of only one variable, the treatments. Frequently, however, we may be interested in studying, simultaneously, the effects of two or more variables. we refer to the variables in which we are interested as factors. The experiment in which two or more factors are investigated simultaneously is called a Factorial Experiment.
the different designated categories of the factors are called levels. Suppose, for example, that we are studying the effect on reaction time of three dosages of second factor of interest in the study is age, and it is thought that two age groups, under 65 years and 65 years and over, should be included. We then have two levels of the age factor. In general, we say that factor A occurs at a levels and factor B occurs at b levels. In factorial experiment we may study not only the effects of individual factors but also, if the experiment is properly conducted, the interaction between factors.

Advantages

The following are the advantages of the Factorial experiment;

1- The interaction of the factors may be studied.

2- There is a saving of time and effort.

3- Since the various factors are combined in one experiment, the results have a wider range of application.