F Test Calculator

The F test calculator compares the equality of two variances.

Validates the data normality, test power, outliers and generates the R syntax.

Enter raw data directly
Enter raw data from excel
Enter summarized data ( n, S)

Enter sample data

Header: You may change groups' name to the real names.
Data: When entering data, press Enter after each value.
The tool will ignore empty cells or non-numeric cells.

Paste sample data from excel

You may copy the data from Excel, Google sheets or any tool that separate data with Tab and Line Feed.
Copy one block of 2 consecutive columns includes the header, and paste below. Click to see example: example from excel
The tool will ignore empty cells or non-numeric cells

validation message


Target: To check if the difference between the population's standard deviations of two groups is significance, using sample data
H0: σ1 = σ2
H1: σ1 < > σ2
F statistic
F =S12
F distribution
F distribution left tailed F distribution two tailed F distribution right tailed


Normal DistributionNormal distribution - the F test for variances is very sensitive to the normality assumption.

Required Sample Data

standard deviationS1, S2 -Sample standard deviations of group1 and group2.
sample sizen1, n2 - Sample size of group1 and group2.

The tool calculates the p-value, the F statistic and the test power.

R syntax

The following R code should produce the same results: