Determine when to reject the null hypothesis by deciding how likely you want it to be that you mistakenly reject the null hypothesis. This is the level of significance, a common choice is 0.05. The output sigA is compared to the chosen level of significance to determine whether to accept or reject the null hypothesis. If sigA is less than the chosen level of significance, reject the null hypothesis. If you reject the null hypothesis, you must acknowledge that at least one level has some effect on the experimental outcome.