Now, that probability threshold, and we've seen this before, is called the significance level, sometimes called alpha. And here, we're going to decide for a significance level of 95%. Or another way to think about it, we want there to be, assuming that the null hypothesis is correct, we want there to be no more than a 5% chance of getting this result here, or no more than a 5% chance of incorrectly rejecting the null hypothesis when it is actually true, or that would be a type 1 error. So if there's less than a 5% probability of this happening, we're going to reject the null hypothesis. And go, less than a 5% probability, given the null hypothesis is true, then we're going to reject the null hypothesis in favor of the alternative. So let's think about this. So we have the null hypothesis.