 Here's a similar problem. I'm going to click a little rectangle, click open, open an Excel. Down here at the bottom we get the spreadsheet. I'm going to double click that to open it. I'm going to find the differences. Equal first minus second. Then I'm just going to copy that down. And then I'm going to get the d bar. And that's just equal average. And then the s is a d is equal to standard deviation. This is a sample. So we get the s version. Take the standard deviation and consider. That's it.