So that is our null hypothesis. And our alternative hypothesis is just going to be, our alternative hypothesis, I'll write it over here, our alternative hypothesis is just that it actually does do something, that our mean, and actually let's say that it actually has an improvement. So that would mean that we have more weight loss. So if we have the mean of group 1, the population mean of group 1 minus the population mean of group 2 should be greater than 0. So this is going to be a one-tailed distribution. Or another way we could view it is that the mean of the difference of the distributions, x1 minus x2, is going to be greater than 0. These are equivalent statements.