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Can be used to test the hypothesis that the population variance are equal?
An F-test (Snedecor and Cochran, 1983) is used to test if the variances of two populations are equal. This test can be a two-tailed test or a one-tailed test. The two-tailed version tests against the alternative that the variances are not equal.
How do you know if population variances are equal?
F Test to Compare Two Variances If the variances are equal, the ratio of the variances will equal 1. For example, if you had two data sets with a sample 1 (variance of 10) and a sample 2 (variance of 10), the ratio would be 10/10 = 1. You always test that the population variances are equal when running an F Test.
What does it mean when the variances are not equal?
For the unequal variance t test, the null hypothesis is that the two population means are the same but the two population variances may differ. The unequal variance t test reports a confidence interval for the difference between two means that is usable even if the standard deviations differ.
What does equal or unequal variance mean?
When the variances are equal it gives essentially the same results as the equal variance test, so a common view is always to use the unequal variance option or always to use the unequal variance version if the results differ.
How is the equality of two population variances tested?
One major application of a test for the equality of two population variances is for checking the validity of the equal variance assumption ( σ 1 2 = σ 2 2) for a two-sample t-test. First we hypothesize two populations of measurements that are normally distributed.
When to reject the null hypothesis in statistics?
We reject the null hypothesis because the test statistic ( t = 3.54) falls in the rejection region: There is (again!) sufficient evidence at the α = 0.05 level to conclude that the average fastest speed driven by the population of male college students differs from the average fastest speed driven by the population of female college students.
Which is the F test for null hypothesis?
The F-distribution. Note: A statistical test of the null hypothesis σ 1 2 = σ 2 2 utilizes the test statistic S 1 2 / S 2 2. It may require either upper tail or lower tail rejection region, depending on which sample variance is larger.
When to use the F test for equality?
An F-test (Snedecor and Cochran, 1983) is used to test if the variances of two populations are equal. This test can be a two-tailed test or a one-tailed test.