Principal Components Analysis

Select menu: Stats | Multivariate Analysis | Principal Components

Principal components analysis finds orthogonal linear combinations of a set of variates that maximize the variation contained within them, thereby displaying most of the original variability in a smaller number of dimensions. It operates on sums of squares and products, or a correlation matrix, or a matrix of variances and covariances, formed from the data variates.

After you have imported your data, from the menu select
Stats | Multivariate Analysis | Principal Components.

Data to be analysed

Used to enter the names of the variates to be analysed. You can transfer multiple selections from Available data by holding the Ctrl key on your keyboard while selecting items, then click to move them all across in one action.

In command mode, the PCP directive has an extended syntax which allows you to specify a matrix, pointer-of-variates, or SSPM as input data.

Analysis based on

Selects whether the analysis is based on the Sums of squares and products, Variance-covariance matrix, or Correlation matrix.

Rotate loadings

Lets you rotate loadings according to either the Varimax or Quartimax criterion.

Action buttons

Run	Run the analysis.
Cancel	Close the dialog without further changes.
Options	Opens a dialog where additional options and settings can be specified for the analysis.
Defaults	Reset options to the default settings. Clicking the right mouse on this button produces a pop-up menu where you can choose to set the options using the currently stored defaults or the Genstat default settings.
Save	Opens a dialog to specify names of structures to save the results from the analysis.
Biplot	Opens a dialog to produce a biplot of the results from the analysis.

Action Icons

	Pin	Controls whether to keep the dialog open when you click Run. When the pin is down the dialog will remain open, otherwise when the pin is up the dialog will close.
	Restore	Restore names into edit fields and default settings.
	Clear	Clear all fields and list boxes.
	Help	Open the Help topic for this dialog.