Implemented long variable names a la spss V12.

[pspp-builds.git] / doc / statistics.texi

diff --git a/doc/statistics.texi b/doc/statistics.texi
index 6014e670e4ed14c818c152c0589817443648b876..26266e4e867c5b6420a326e1e73244b193f23b82 100644 (file)
--- a/doc/statistics.texi
+++ b/doc/statistics.texi
@@ -10,6 +10,7 @@ far.
 @menu
 * DESCRIPTIVES::                Descriptive statistics.
 * FREQUENCIES::                 Frequency tables.
+* EXAMINE::                     Testing data for normality.
 * CROSSTABS::                   Crosstabulation tables.
 * T-TEST::                      Test hypotheses about means.
 * ONEWAY::                      One way analysis of variance.
@@ -105,7 +106,7 @@ in the order that they are specified on the VARIABLES subcommand.  The A
 and D settings request an ascending or descending sort order,
 respectively.
 
-@node FREQUENCIES, CROSSTABS, DESCRIPTIVES, Statistics
+@node FREQUENCIES, EXAMINE, DESCRIPTIVES, Statistics
 @section FREQUENCIES
 
 @vindex FREQUENCIES
@@ -212,7 +213,82 @@ boundaries of the data set divided into the specified number of ranges.
 For instance, @code{/NTILES=4} would cause quartiles to be reported.
 
 
-@node CROSSTABS, T-TEST, FREQUENCIES, Statistics
+@node EXAMINE, CROSSTABS, FREQUENCIES, Statistics
+@comment  node-name,  next,  previous,  up
+@section EXAMINE
+@vindex EXAMINE
+
+@cindex Normality, testing for
+
+@display
+EXAMINE
+        VARIABLES=var_list [BY factor_list ]
+        /STATISTICS=@{DESCRIPTIVES, EXTREME[(n)], ALL, NONE@}
+        /PLOT=@{STEMLEAF, BOXPLOT, NPPLOT, SPREADLEVEL(n), HISTOGRAM, 
+              ALL, NONE@}
+        /CINTERVAL n
+        /COMPARE=@{GROUPS,VARIABLES@}
+        /ID=@{case_number, var_name@}
+        /@{TOTAL,NOTOTAL@}
+        /PERCENTILE=[value_list]=@{HAVERAGE, WAVERAGE, ROUND, AEMPIRICAL, EMPIRICAL @}
+        /MISSING=@{LISTWISE, PAIRWISE@} [@{EXCLUDE, INCLUDE@}] 
+               [@{NOREPORT,REPORT@}]
+
+@end display
+
+The @cmd{EXAMINE} command is used to test how closely a distribution is to a 
+normal distribution.  It also shows you outliers and extreme values.
+
+The VARIABLES subcommand specifies the dependent variables and the
+independent variable to use as factors for the analysis.   Variables
+listed before the first BY keyword are the dependent variables.
+The dependent variables may optionally be followed by a list of
+factors which tell PSPP how to break down the analysis for each
+dependent variable.  The format for each factor is 
+@display
+var [BY var].
+@end display
+
+
+The STATISTICS subcommand specifies the analysis to be done.  
+DESCRIPTIVES will produce a table showing some parametric and
+non-parametrics statistics.  EXTREME produces a table showing extreme
+values of the dependent variable.  A number in parentheses determines
+how many upper and lower extremes to show.  The default number is 5.
+
+
+The PLOT subcommand specifies which plots are to be produced if any.
+
+The COMPARE subcommand is only relevant if producing boxplots, and it is only 
+useful there is more than one dependent variable and at least one factor.   If 
+/COMPARE=GROUPS is specified, then one plot per dependent variable is produced,
+containing boxplots for all the factors.
+If /COMPARE=VARIABLES is specified, then one plot per factor is produced, each 
+each containing one boxplot per dependent variable.
+If the /COMPARE subcommand is ommitted, then PSPP uses the default value of 
+/COMPARE=GROUPS.
+
+The CINTERVAL subcommand specifies the confidence interval to use in
+calculation of the descriptives command.  The default it 95%.
+
+The PERCENTILES subcommand specifies which percentiles are to be calculated, 
+and which algorithm to use for calculating them.  The default is to
+calculate the 5, 10, 25, 50, 75, 90, 95 percentiles using the
+HAVERAGE algorithm.
+
+The TOTAL and NOTOTAL subcommands are mutually exclusive.  If NOTOTAL
+is given and factors have been specified in the VARIABLES subcommand,
+then then statistics for the unfactored dependent variables are
+produced in addition to the factored variables.  If there are no
+factors specified then TOTAL and NOTOTAL have no effect.
+
+@strong{Warning!}
+If many dependent variable are given, or factors are given for which
+there are many distinct values, then @cmd{EXAMINE} will produce a very
+large quantity of output.
+
+
+@node CROSSTABS, T-TEST, EXAMINE, Statistics
 @section CROSSTABS
 
 @vindex CROSSTABS
@@ -525,7 +601,7 @@ of variable preceding @code{WITH} against variable following
 
 @node ONEWAY, , T-TEST, Statistics
 @comment  node-name,  next,  previous,  up
-@section Oneway
+@section ONEWAY
 
 @vindex ONEWAY
 @cindex analysis of variance