 If the value of "z" is sufficiently large, it is unlikely that the deviations would occur by chance and thus the hypothesis of Hardy Weinberg Equilibrium can be rejected.To determine if "z" is significantly larger or smaller than expected under Hardy Weinberg Equilibrium, find "the probability of observing" a value as or more extreme as the observed "z" "under the null hypothesis".The tail probability is normally used, ℙ("y" > "z"), where "y" is standard normal random variable.