### Excel Add-In: OLS Regression and OLSReg Function

**Warning:** When you download the add-in, make sure that you save it as an ".xla" file. Internet Explorer often changes the file extension to ".xls".

This add-in, OLSRegression.xla, enables OLS estimation with more than 16 Xs (the limit of Excel's LINEST function and Data Analysis: Regression tool) and it reports robust SEs (along with the usual regression output). Also, unlike Excel's regression tools, it handles missing values. This add-in does so by running regressions using only observations with non-missing values for all variables.

Once you have installed the add-in you will have access to the OLSReg function, which gives exactly the same output as the add-in, but which recomputes whenever the data changes. The OLSReg function is analogous to Excel's LINEST function, but it displays its output in much more readable form.

The OLSReg function was not included on the CD that shipped with the first edition of the book.

The installation instructions describe how to use the OLSReg function as well as additional features and advantages over Excel's built-in regression options. Right-click to download the OLSRegression.xla file when you are ready.

**Files**

Installation Instructions

OLSRegression.xla

OLSRegressionExample.xls