Fixed the handling of MISSING values in t-test

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

diff --git a/doc/pspp.texi b/doc/pspp.texi
index 564e36ec7d6e7d9d34235d96f57a4fe189f9d13e..cda0308fd0aa9c87012c6f88796098ab9325337e 100644 (file)
--- a/doc/pspp.texi
+++ b/doc/pspp.texi
@@ -7484,6 +7484,7 @@ far.
 @node DESCRIPTIVES, FREQUENCIES, Statistics, Statistics
 @section DESCRIPTIVES
 
+@vindex DESCRIPTIVES
 @display
 DESCRIPTIVES
         /VARIABLES=var_list
@@ -7573,6 +7574,7 @@ respectively.
 @node FREQUENCIES, CROSSTABS, DESCRIPTIVES, Statistics
 @section FREQUENCIES
 
+@vindex FREQUENCIES
 @display
 FREQUENCIES
         /VARIABLES=var_list
@@ -7675,6 +7677,7 @@ particular percentiles can be requested with the PERCENTILES subcommand.
 @node CROSSTABS, T-TEST, FREQUENCIES, Statistics
 @section CROSSTABS
 
+@vindex CROSSTABS
 @display
 CROSSTABS
         /TABLES=var_list BY var_list [BY var_list]@dots{}
@@ -7859,9 +7862,9 @@ Fixes for any of these deficiencies would be welcomed.
 
 @node T-TEST, , CROSSTABS, Statistics
 @comment  node-name,  next,  previous,  up
-
 @section T-TEST
 
+@vindex T-TEST
 @display
 T-TEST
         /MISSING=@{ANALYSIS,LISTWISE@} @{EXCLUDE,INCLUDE@}
@@ -7904,14 +7907,16 @@ in the tests.  The default value is 0.95.
 The @cmd{MISSING} subcommand determines the handling of missing
 variables.  
 If INCLUDE is set, then user-missing values are included in the
-calculations.  
+calculations, but system-missing values are not.
 If EXCLUDE is set, which is the default, user-missing
-values are excluded.  
-If LISTWISE is set, then
-the entire case is excluded whenever any value in that case has a
-system-missing or, if INCLUDE is set, user-missing value.
-If ANALYSIS is set, then cases are excluded only where a value used in
-the analysis has a system-missing or, if INCLUDE is set, user-missing value.
+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}, @cmd{/PAIRS} or 
+@cmd{/GROUPS} subcommands contains a missing value.   
+If ANALYSIS is set, then missing values are excluded only in the analysis for
+which they would be needed. This is the default.
 
 
 @menu
@@ -7941,12 +7946,25 @@ The @cmd{GROUPS} subcommand invokes Independent Samples mode or
 `Groups' mode. 
 This mode is used to test whether two groups of values have the
 same population mean.
+In this mode, you must also use the @cmd{/VARIABLES} subcommand to
+tell PSPP the dependent variables you wish to test.
+
 The variable given in the @cmd{GROUPS} subcommand is the independent
 variable which determines to which group the samples belong.
 The values in parentheses are the specific values of the independent
 variable for each group.
-In this mode, you must also use the @cmd{/VARIABLES} subcommand to
-tell PSPP the dependent variables you wish to test.
+If the parentheses are omitted and no values are given, the default values 
+of 1.0 and 2.0 are assumed.
+
+If the independent variable is numeric, 
+it is acceptable to specify only one value inside the parentheses.
+If you do this, cases where the independent variable is
+less than  or equal to this value belong to the first group, and cases
+greater than this value belong to the second group.
+When using this form of the @cmd{GROUPS} subcommand, missing values in
+the independent variable are excluded on a listwise basis, regardless
+of whether @cmd{/MISSING=LISTWISE} was specified.
+
 
 @node Paired Samples Mode, , Independent Samples Mode, T-TEST
 @comment  node-name,  next,  previous,  up