ABSTRACT
The most general procedure appropriate to the cases is known as analysis of variance. Analysis of variance is based on the idea that the total variation associated with the values of a sample can be divided into component parts in order to arrive at independent estimates of a population variance. The analysis of variance procedure can form the basis of a highly effective significance test on the differences of the means of several samples. Statisticians have shown that a single sample can be randomly divided into a number of separate groups and this can yield two independent unbiased estimates of a common population variance. The within-samples degrees of freedom can be obtained most directly by subtraction of the between-samples degrees of freedom from the total degrees of freedom.
