And if it's below some threshold, we reject the null hypothesis and it suggests the alternative. And over here, the way we do that is we find an associated Z value for that P, for that sample proportion. And the way that we calculate it, we say, okay, look, our Z is going to be how many of the sampling distributions, standard deviations, are we away from the mean? And remember, the mean of the sampling distribution is going to be the population proportion. So here, we got this sample statistic, this sample proportion. The difference between that and the assumed proportion, remember, when we do these significance tests, we try to figure out the probability assuming the null hypothesis is true. And so when we see this P sub zero, this is the assumed proportion from the null hypothesis.