After performing the Grids | Calculate | Residuals command:
In the worksheet, click the column letter for the column containing the residual values to select the entire column. To get the statistics for just a portion of the residual values, select only those particular values.
Choose the Data | Data | Statistics command. Specify the desired parameters to be reported.
If Show in a window is selected, the Statistics Results window is displayed with the statistical information on the residual data. If the Copy to worksheet option is selected, the residual results are placed directly into the specified columns of the worksheet.
Calculating the Value of the Surface at a Point