Using the Regression Tool

One advantage of the Regression tool is that you don't have to rearrange the original data (although you still can if you want to). The regression tool is part of the Data Analysis ToolPak. This is one of Excel's Add-ins. That means that it might not be "active" in your installation of Excel. To check, go to the Data ribbon and look at the right end. If Data Analysis is there, you're fine. If not, you'll need to go through the Add-in process to activate it. According to our LIS people, this should be working on all of the campus computers.

Once you're able to get the above screen, click on Data Analysis and look for Regression. You'll probably have to scroll down a bit to find it.

Seledt it and click OK. You'll get a new window to set up the regression analysis. Be careful to make sure that you've got your X and Y data in the correct slots. You'll usually have labels so check the "Label" box. The Output Range is up to you. Many people like to have it on a new worksheet. For smaller problems, I like to put it just a few columns to the right of my data. To get residuals, you need to click the Residual and Residual Plots boxes.

Initially, your output is a bit of a mess. There are a couple of problems. Some of the column widths are too small and none of the numbers have reasonable formats. There's also a LOT of output that we just don't need.

Here's what it looks like with better formatting and the unneeded parts greyed out.