F-Test two samples for variances
This example shows you how to perform an F-Test. The F-Test is used to test the null hypothesis that the variances of two data populations are equal. The distribution of data is assumed to be normal.
H0: σ12 = σ22
H1: σ?12 ≠ σ22
The measured dissolving times of two different brands of instant coffe are:
To perform an F-Test, execute the following steps:
1. On the menu, select "F-Test Two-Sample for Variances" and click OK.
2. Click in the "Data 1" cellrange box and select the range B2:B9.
3. Click in the "Data 2" cellrange box and select the range C2:C7.
The default Alpha-value is the commonly used value 0.05. This means a 95% significance level.
4. Click in the "Output Range" cellrange box and select cell E1.
5. Click OK.
Modeller returns the p-values. If p > 0,05, we accept H0. If < 0,05 then we reject H0. In this case 0,93 > 0,05, therefore we accept the null hypothesis: the variances of the two samples are equal at 95% significance-level; specifically the variances of dissolving times for coffees are not different.