Rotates factor loadings from a principal components analysis according to either the
varimax or quartimax criterion. Principal components analysis defines a set of dimensions
(sometimes called axes) that are linear combinations of the original variables. The individual
coefficients of these combinations are called loadings, and can be used to interpret the dimensions.
With principal components analysis, the loadings must lie in the range [-1, +1]. When several dimensions
are considered it is possible to define an equivalent set of new dimensions, whose loadings are linear combinations
of the original loadings. If the absolute values of the loadings for a new dimension are either close to 0 or close to 1,
you can interpret the dimension as mainly representing only those original variables with large positive (or negative) loadings.
You may sometimes want new dimensions determined by loadings like these, because they are easier to interpret. The methods by
which these new dimensions can be obtained are generally known collectively as factor rotation because the new dimensions
represent a rotation of the axes of the original dimensions.
Display
This specifies which items of output are to be produced by the analysis.
Communalities
displays the communalities of the variables
Rotation
displays the rotated factors
Method
Controls the method used for the factor rotation. The Varimax rotation, maximizes the variance
of the squares of the loadings within each new dimension: the effect of this rotation should be to spread out the
squared-loadings to the extremes of their range. The Quartimax rotation uses uses the fourth
power of the loadings instead of the second power.
Save
This allows you to save results from the factor rotation in GenStat data structures. After checking the appropriate boxes,
you need to type the names for the identifiers of the data structures into the corresponding In:
fields.
Rotated Loadings
Matrix
of the rotated loadings
Display in Spreadsheet
The saved results will also be displayed within a new spreadsheet window.