X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=doc%2Fstatistics.texi;fp=doc%2Fstatistics.texi;h=b79997bc15edf71ce6b84e7c71613c16c390b2e8;hb=9e8fca7bd38927d335b81f5f1a282deff665e024;hp=0cfceb225afa5d59988a7a426f5042866d0291a2;hpb=2088d7438791ad96dda2037a6ac7e9b0f3998c8b;p=pspp

diff --git a/doc/statistics.texi b/doc/statistics.texi
index 0cfceb225a..b79997bc15 100644
--- a/doc/statistics.texi
+++ b/doc/statistics.texi
@@ -1781,7 +1781,15 @@ categories, they include all the values listed individually and all
 values with value labels that are covered by ranges or @code{MISSING}
 or @code{OTHERNM}.
 
-@c TODO
+The following example syntax and output show the effect of
+@code{EMPTY=EXCLUDE} for the @code{qns1} variable, in which 0 is labeled
+``None'' but no cases exist with that value:
+
+@example
+CTABLES /TABLE=qns1.
+CTABLES /TABLE=qns1 /CATEGORIES VARIABLES=qns1 EMPTY=EXCLUDE.
+@end example
+@psppoutput {ctables31}
 
 @node CTABLES Titles
 @subsection Titles
@@ -1820,8 +1828,6 @@ The expression specified on the @code{TABLE} command.  Summary
 and measurement level specifications are omitted, and variable labels are used in place of variable names.
 @end table
 
-@c TODO example
-
 @node CTABLES Table Formatting
 @subsection Table Formatting
 
@@ -1891,8 +1897,6 @@ Show variable name and label.
 Show nothing.
 @end table
 
-@c TODO example
-
 @node CTABLES Missing Value Treatment
 @subsection Missing Value Treatment
 
@@ -1900,26 +1904,40 @@ The @code{TABLE} subcommand on @code{CTABLES} specifies two different
 kinds of variables: variables that divide tables into cells (which are
 always categorical) and variables being summarized (which may be
 categorical or scale).  @pspp{} treats missing values differently in
-each kind of variable:
+each kind of variable, as described in the sections below.
+
+@node CTABLES Missing Values for Cell-Defining Variables
+@subsubsection Missing Values for Cell-Defining Variables
 
-@itemize @bullet
-@item
 For variables that divide tables into cells, per-variable category
-options determine which data is analyzed.  If any of the categories
-for such a variable would exclude a case, then that case is not
-included.
+options, as described in @ref{CTABLES Per-Variable Category Options},
+determine which data is analyzed.  If any of the categories for such a
+variable would exclude a case, then that case is not included.
 
-@item
-The treatment of missing values in variables being summarized varies
-between scale and scale and categorical variables.  The following
-section describes their treatment in detail.
+As an example, consider the following entirely artificial dataset, in
+which @samp{x} and @samp{y} are categorical variables with missing
+value 9, and @samp{z} is scale:
 
-By default, each summarized variable is considered separately for
-missing value treatment.  A section below describes how to consider
-missing values listwise for summarizing scale variables.
-@end itemize
+@psppoutput{ctables32}
 
-@c TODO example
+Using @samp{x} and @samp{y} to define cells, and summarizing @samp{z},
+by default @pspp{} omits all the cases that have @samp{x} or @samp{y} (or both)
+missing:
+
+@example
+CTABLES /TABLE x > y > z [SUM].
+@end example
+@psppoutput{ctables33}
+
+If, however, we add @code{CATEGORIES} specifications to include
+missing values for @samp{y} or for @samp{x} and @samp{y}, the output
+table includes them, like so:
+
+@example
+CTABLES /TABLE x > y > z [SUM] /CATEGORIES VARIABLES=y MISSING=INCLUDE.
+CTABLES /TABLE x > y > z [SUM] /CATEGORIES VARIABLES=x y MISSING=INCLUDE.
+@end example
+@psppoutput{ctables34}
 
 @node CTABLES Missing Values for Summary Variables
 @subsubsection Missing Values for Summary Variables