Variance ratio test (F test) 

The Variance ratio test (F test) is used to compare the variances of two samples. 

Required input 

In the dialog box first identify the variables for sam l

p e 1 and sample 2.  Use the 

 button to select 

variables and selection criteria in the variables list. 

Options 

Logarithmic transformation: select this option if the data are positively skewed. 

Results 

The program displays summary statistics and the variances of the two samples.  Next the results of the 

variance ratio test and the F statistic is given, which is the ratio of the larger variance over the smaller, with 

its associated (two sided) P value.  If the P value is less than the conventional 0.05, the null hypothesis is 

rejected a

  nd the conclusion is that the two variances differ significantly.   

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