Assumption of F- Test
The theoretical assumption on which F test is based are:
1.The populations for each sample must be normally distributed with identical mean and variance.
2.All sample observation must be randomly selected and independent.
3. The ration of αa2 to α22 should be equal to or greater than. This is the reason that larger variance is divided by the smaller variance.
4. Since the F distribution is always formed by a ratio of squared values it can never be a negative number. All F distribution are unmoral and are skewed to the right. They tend to become more nearly symmetrical as V_{1} and v_{2} increase.
5.The total variance of the various sources of variance should be additive.
Total sum of squares = sum of squares between the groups + sum of squares within the groups.