* EXAMINE:: Testing data for normality.
* CORRELATIONS:: Correlation tables.
* CROSSTABS:: Crosstabulation tables.
+* FACTOR:: Factor analysis and Principal Components analysis
* NPAR TESTS:: Nonparametric tests.
* T-TEST:: Test hypotheses about means.
* ONEWAY:: One way analysis of variance.
]
[ /PRINT=@{TWOTAIL, ONETAIL@} @{SIG, NOSIG@} ]
+ [ /STATISTICS=DESCRIPTIVES XPROD ALL]
[ /MISSING=@{PAIRWISE, LISTWISE@} @{INCLUDE, EXCLUDE@} ]
@end display
This is the default.
If LISTWISE is set, then the entire case is excluded from analysis
-whenever any variable specified in the any @cmd{/VARIABLES} subcommand
+whenever any variable specified in any @cmd{/VARIABLES} subcommand
contains a missing value.
If PAIRWISE is set, then a case is considered missing only if either of the
values for the particular coefficient are missing.
0.05 are highlighted.
If SIG is specified, then no highlighting is performed. This is the default.
-
+@cindex covariance
+The STATISTICS subcommand requests additional statistics to be displayed. The keyword
+DESCRIPTIVES requests that the mean, number of non-missing cases, and the non-biased
+estimator of the standard deviation are displayed.
+These statistics will be displayed in a separated table, for all the variables listed
+in any /VARIABLES subcommand.
+The XPROD keyword requests cross-product deviations and covariance estimators to
+be displayed for each pair of variables.
+The keyword ALL is the union of DESCRIPTIVES and XPROD.
@node CROSSTABS
@section CROSSTABS
Fixes for any of these deficiencies would be welcomed.
+@node FACTOR
+@section FACTOR
+
+@vindex FACTOR
+@cindex factor analysis
+@cindex principal components analysis
+@cindex principal axis factoring
+@cindex data reduction
+
+@display
+FACTOR VARIABLES=var_list
+
+ [ /METHOD = @{CORRELATION, COVARIANCE@} ]
+
+ [ /EXTRACTION=@{PC, PAF@}]
+
+ [ /PRINT=[INITIAL] [EXTRACTION] [UNIVARIATE] [CORRELATION] [COVARIANCE] [DET] [SIG] [ALL] [DEFAULT] ]
+
+ [ /PLOT=[EIGEN] ]
+
+ [ /FORMAT=[SORT] [BLANK(@var{n})] [DEFAULT] ]
+
+ [ /CRITERIA=[FACTORS(@var{n})] [MINEIGEN(@var{l})] [ITERATE(@var{m})] [ECONVERGE (@var{delta})] [DEFAULT] ]
+
+ [ /MISSING=[@{LISTWISE, PAIRWISE@}] [@{INCLUDE, EXCLUDE@}] ]
+@end display
+
+The FACTOR command performs Factor Analysis or Principal Axis Factoring on a dataset. It may be used to find
+common factors in the data or for data reduction purposes.
+
+The VARIABLES subcommand is required. It lists the variables which are to partake in the analysis.
+
+The /EXTRACTION subcommand is used to specify the way in which factors (components) are extracted from the data.
+If PC is specified, then Principal Components Analysis is used. If PAF is specified, then Principal Axis Factoring is
+used. By default Principal Components Analysis will be used.
+
+The /METHOD subcommand should be used to determine whether the covariance matrix or the correlation matrix of the data is
+to be analysed. By default, the correlation matrix is analysed.
+
+The /PRINT subcommand may be used to select which features of the analysis are reported:
+
+@itemize
+@item UNIVARIATE
+ A table of mean values, standard deviations and total weights are printed.
+@item INITIAL
+ Initial communalities and eigenvalues are printed.
+@item EXTRACTION
+ Extracted communalities and eigenvalues are printed.
+@item CORRELATION
+ The correlation matrix is printed.
+@item COVARIANCE
+ The covariance matrix is printed.
+@item DET
+ The determinant of the correlation or covariance matrix is printed.
+@item SIG
+ The significance of the elements of correlation matrix is printed.
+@item ALL
+ All of the above are printed.
+@item DEFAULT
+ Identical to INITIAL and EXTRACTION.
+@end itemize
+
+If /PLOT=EIGEN is given, then a ``Scree'' plot of the eigenvalues will be printed. This can be useful for visualising
+which factors (components) should be retained.
+
+The /FORMAT subcommand determined how data are to be displayed in loading matrices. If SORT is specified, then the variables
+are sorted in descending order of significance. If BLANK(@var{n}) is specified, then coefficients whose absolute value is less
+than @var{n} will not be printed. If the keyword DEFAULT is given, or if no /FORMAT subcommand is given, then no sorting is
+performed, and all coefficients will be printed.
+
+The /CRITERIA subcommand is used to specify how the number of extracted factors (components) are chosen. If FACTORS(@var{n}) is
+specified, where @var{n} is an integer, then @var{n} factors will be extracted. Otherwise, the MINEIGEN setting will
+be used. MINEIGEN(@var{l}) requests that all factors whose eigenvalues are greater than or equal to @var{l} are extracted.
+The default value of @var{l} is 1. The ECONVERGE and ITERATE settings have effect only when iterative algorithms for factor
+extraction (such as Principal Axis Factoring) are used. ECONVERGE(@var{delta}) specifies that iteration should cease when
+the maximum absolute value of the communality estimate between one iteration and the previous is less than @var{delta}. The
+default value of @var{delta} is 0.001.
+The ITERATE(@var{m}) setting sets the maximum number of iterations to @var{m}. The default value of @var{m} is 25.
+
+The @cmd{MISSING} subcommand determines the handling of missing variables.
+If INCLUDE is set, then user-missing values are included in the
+calculations, but system-missing values are not.
+If EXCLUDE is set, which is the default, user-missing
+values are excluded as well as system-missing values.
+This is the default.
+If LISTWISE is set, then the entire case is excluded from analysis
+whenever any variable specified in the @cmd{VARIABLES} subcommand
+contains a missing value.
+If PAIRWISE is set, then a case is considered missing only if either of the
+values for the particular coefficient are missing.
+The default is LISTWISE.
+
+
@node NPAR TESTS
@section NPAR TESTS