# Residual Analysis - Residuals Tab

Multiple Regression - Computational Approach

Select the Residuals tab of the Residual Analysis dialog to access options to review graphs of various types of residuals. All residual plots and spreadsheets are unlimited/user-limited as defined by the Maximum number of rows (cases) in a single results Spreadsheet or Graph box on the Residual Analysis dialog - Advanced tab. Note that when Pairwise deletion is selected in the MD deletion group box in the Startup Panel, the program will substitute any missing values with the respective means in the computations for predicted and residual values (and related statistics).

Histogram of residuals. Click the Histogram of residuals button to display a histogram for the residual type selected in the Type of residual group box (see below). These statistics are briefly explained in Residuals and predicted values.

Casewise plot of residuals. Click the Casewise plot of residuals button to display a spreadsheet in which the selected values are plotted in the left-most column. At the same time, all residual statistics are computed and can be reviewed (in the subsequent columns of the spreadsheet). Plotted residual values are for the residual type selected in the Type of residual group box.

Residuals vs. independent var. Click the Residuals vs. independent var. button to display a scatterplot of various residual values (for the dependent variable) with any variable in the data file, regardless of whether it was included in the regression analysis. This option is not available if the current analysis was performed via Fixed Nonlinear Regression. After clicking this button, the standard variable selection dialog will be displayed that allows you to enter the other independent variable for the plot. This option allows you to explore the relationship between the residualized dependent variable with other variables in your data file. Note the scatterplot will include residual values for the residual type selected in the Type of residual group box.

Histogram of observed. Click the Histogram of observed button to display a histogram (frequency distribution) of the observed values for the dependent variable, and superimpose the expected normal distribution values over this plot.

Type of residual. Select the Type of residual that you want to use in the plots. The available residual values are Raw residuals, Standard residuals, Mahalanobis distances, Deleted residuals, and Cook's distances. These statistics are briefly explained in Residuals and predicted values.