And then this distribution right here is going to have some standard deviation. It's going to have some standard deviation. So it's the standard deviation of the distribution of x, of the mean of 1 of x1 minus the sample mean of x2. It's going to have some standard deviation here. And we want to make an inference about this. I guess this is the best way to think about it. We want to get a 95% confidence interval based on our sample.