66 WORKING WITH SAMPLE DATA find F = = 0.498. So we will reject the null hypothesis if the calculated test statistic falls above F = 1.943 or below F = 0.498. Test Statistic: Observed Significance Level: To find the p- value for the F test statistic, we use the function in Excel =2*Fdist(3.231,30,40). We have to double the output from the Fdist function because it assumes a one-tailed test. p- value = 0.0006 Conclusion: Since the test statistic of F = 3.231 falls well above the upper critical bound of F = 1.943, we reject H 0 with at least 95% confidence. Likewise, since the p- value of 0.0006 is less than