In the last video, we came up with a 95% confidence interval for the mean weight loss between the low-fat group and the control group. In this video, I actually want to do a hypothesis test to see really the test if this data makes us believe that the low-fat diet actually does anything at all. And to do that, let's set up our null and alternative hypotheses. 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.