In statistics, a Q-Q Plot (“Q” stands for Quantile) creates a graphical comparison between two distributions by plotting their quantiles against each other.
NumXL provides an intuitive interface to help Excel users construct a Q-Q Plot of an empirical sample data distribution against a theoretical Gaussian distribution. In this tutorial, we’ll demonstrate the steps to construct a Q-Q Plot using NumXL functions in Excel.
- Select an empty cell to store the histogram table
- Locate the Descriptive Statistics (DESC STAT) icon in the toolbar (or menu in Excel 2003) and click the down-arrow. When the drop-down menu appears, select “Q-Q Plot”
- The Q-Q Plot dialog box appears
- Select the cell-range for the input data
Note: The table output range is set to the selected empty cell in your worksheet.
- Next, select the number of quantiles (number of points in the Q-Q Plot). The number of bins is set initially to 10.
- Click OK.
The QQ-Plot wizard generates the output table and plots the graph on the right