Principal Components and Factor Analysis

Select the Advanced tab of the Review Descriptive Statistics dialog box to access options to compute descriptive statistics for the selected variables, and, if a raw data input file format is currently analyzed, produce graphs that allow you to visually judge the underlying assumptions of factor analysis. Note that if a correlation matrix input file format is currently analyzed, only the Means & Standard Deviations, Correlations, and Covariances buttons will be available on the Advanced tab.

Means & SD. Click the Means & SD button to produce a spreadsheet with the descriptive statistics for the variables in the analysis. If a raw data file is analyzed, a Graph of Input Data for that spreadsheet is the histogram with fitted normal distribution.

Correlations. Click the Correlations button to produce a spreadsheet with the current correlation matrix. If a raw data file is analyzed, then a Graph of Input Data for that spreadsheet is the scatterplot with the fitted regression line. If matrix ill-conditioning was detected during the factoring process, then this matrix will have been slightly modified (see Note).

Scatterplot Matrix . Click the Scatterplot Matrix button to produce a scatterplot matrix for the variables in the current analysis.

Covariances. Click the Covariances button to produce a spreadsheet with the current covariance matrix. If a raw data file is analyzed, a Graph of Input Data for that spreadsheet is the scatterplot with the fitted regression line. If matrix ill-conditioning was detected during the factoring process, this matrix will have been slightly modified (see Note).

Box & whisker. Click the Box & whisker button to produce box and whisker plots for the variables in the current analysis.

Histograms. Click the Histograms button to produce histograms of the distributions of variables in the current analysis. The plots will also include the expected normal distribution curves.

Normal prob. plots. Click the Normal prob. plots button to produce a cascade of normal probability plots for the selected variables, one plot per selected variable. For more information on how the standard normal probability plot is constructed, see Computation Note for Normal Probability Plots.

3D bivariate distrib. Click the 3D bivariate distrib. button to display a standard variable selection dialog box, in which you select two lists of variables (from among those originally selected via the Factor Analysis Startup Panel - Quick tab). Then click the OK button to produce a cascade of 3D histograms for selected pairs of variables, one plot per pair. 3D histograms will be produced for each variable in the first list with each variable in the second list.

2D scatterp. Click the 2D scatterp. button to display a standard variable selection dialog box, in which you select two lists of variables (from among those originally selected via the Factor Analysis Startup Panel - Quick tab). Then click the OK button to produce a cascade of scatterplots for selected pairs of variables, one plot per variable pair (i.e., correlation). Each plot will also show the regression line and the standard error of the predicted values (as error lines).

3D scatterp. Click the 3D scatterp. button to display a standard variable selection dialog box, in which you select three lists of variables (from among those originally selected via the Factor Analysis Startup Panel - Quick tab). Then click the OK button to produce a 3D scatterplot for the selected triplet of variables.

Surface. Click the Surface button to display a standard variable selection dialog box, in which you select three lists of variables (from among those originally selected via the Factor Analysis Startup Panel - Quick tab). Then click the OK button to produce a 3D scatterplot for the selected triplet of variables with a quadratic surface fit to the data.