So I have some data here in a spreadsheet. You could use Microsoft Excel or you could use Google Spreadsheets. And we're gonna use the spreadsheet to quickly calculate some parameters. Let's say this is the population. Let's say this is, we're looking at a population of students and we wanna calculate some parameters, and this is their ages, and we wanna calculate some parameters on that. And so, first I'm gonna calculate it using the spreadsheet. And then we're gonna think about how those parameters change as we do things to the data.