And the way we're going to do it in this video, and this is really the way it's done in pretty much all of science, is you say, OK, let's assume that the null hypothesis is true. If the null hypothesis was true, what is the probability that we would have gotten these results with the sample? And if that probability is really, really small, then the null hypothesis probably isn't true. We could probably reject the null hypothesis and we'll say, well, we kind of believe in the alternative hypothesis. So let's think about that. Let's assume that the null hypothesis is true. And so if we assume the null hypothesis is true, let's try to figure out the probability that we would have actually gotten this result, that we would have actually gotten a sample mean of 1.05 seconds with a standard deviation of 0.5 seconds.