If the Analysis feedback tool is not enabled in Excel by default, follow these steps to enable it. 

1. Open Excel.
2. Click File on the top left.
3. On the left side, at the bottom, click Options.
   1. If Options does not appear, first click More, then click Options.
4. In the new Options Window, on the left side towards the bottom, click Add-ins.
5. On the bottom of the window, make sure the "Manage" dropdown is set to Excel Add-ins.
6. Click Go...
7. In the new window, click the checkbox next to Analysis Toolpak and any other add-ins that you want.
8. Click Ok.

Once this is done you should have the Data Analysis tool under the Data tab to use the regression tool.