Before carrying out a statistic test to compare two sample means in a comparative study, we have to first test whether the sample variances are significantly different or not. The inferential statistic test used is called Fisher’s F ratio-test devised by Sir Ronald Fisher, a famous statistician. It is widely used as a test of statistical significance.
R and F-test
The Fisher F-test statistic is based on the ratio of two experimentally observed variance, which are squared standard deviations. Therefore, it is useful to test whether two standard deviations s1 and s2, calculated from two independent data sets are significantly different in terms of precision from each other. Read more …The variance ratio F-test statistic