And then the null hypothesis is no, your mean with the drug is going to be the same thing as the population mean. It has no effect. In this situation, where we're really just testing to see if it had an effect, whether an extreme positive effect or an extreme negative effect would have both been considered an effect, we did something called a two-tailed test. This is called a two-tailed test. Because frankly, a super high response time, if you had a response time that was more than 3 standard deviations, that would have also made us likely to reject the null hypothesis. So we were dealing with kind of both tails. You could have done a similar type of hypothesis test with the same experiment, where you only have a one-tailed test.