So our null hypothesis should be that, hey, this low-fat diet does nothing. And if the low-fat diet does nothing, that means that the mean, the population mean on our low-fat diet minus the population mean on our control should be equal to 0. And this is a completely equivalent statement to saying that the mean of the sampling distribution of our low-fat diet minus the mean of the sampling distribution of our control should be equal to 0. And that's because we've seen this multiple times. The mean of your sampling distribution is going to be the same thing as your population mean. So this is the same thing as that. That is the same thing as that.