Peter N. answered 12/13/21
PhD with over 15 years of teaching social science statistics.
First, square the standard deviations to get the variances:
3.7^2 = 13.69
3.1^2 = 9.61
Next, calculate the F ratio by dividing the first variance by the second
F = 13.69 / 9.61
F = 1.4246
Next, find the critical value of F with the given degrees of freedom at alpha = .05.
The degrees of freedom are n-1 so, 8 (9 -1) and 8 (9 -1)
You will need to look up the critical value in a table or have it calculated online, you don't want to calculate critical values by hand!
In the F table, the critical value at alpha = .05 with 8 and 8 degrees of freedom is 3.44.
The test result is significant if the calculated F is greater than the critical F
In our case, the calculated F, 1.4246, is less than the critical F, 3.44. This means the test is not significant and the SD's are not significantly different.