@i{axis} + @i{axis}
@i{axis} > @i{axis}
(@i{axis})
-@i{axis} @t{(}@i{summary} [@i{string}] [@i{format}]@t{)}
+@i{axis} @t{[}@i{summary} [@i{string}] [@i{format}]@t{]}
@end display
The following subcommands precede the first @code{TABLE} subcommand
@item @code{COUNT} (``Count'')
The sum of weights in a cell.
+If @code{CATEGORIES} for one or more of the variables in a table
+include missing values (@pxref{CTABLES Per-Variable Category
+Options}), then some or all of the categories for a cell might be
+missing values. @code{COUNT} counts data included in a cell
+regardless of whether its categories are missing.
+
@item @code{@i{area}PCT} or @code{@i{area}PCT.COUNT} (``@i{Area} %'')
A percentage within the specified @var{area}.
A percentage of total values within the specified @var{area}.
@end table
-The following summary functions apply only to scalar variables:
+The following summary functions apply only to scalar variables or
+totals and subtotals for categorical variables. Be cautious about
+interpreting the summary value in the latter case, because it is not
+necessarily meaningful; however, the mean of a Likert scale, etc.@:
+may have a straightforward interpreation.
@table @asis
@item @code{MAXIMUM} (``Maximum'')
The sum.
@item @code{TOTALN} (``Total N'')
-The sum of total count weights.
+The sum of weights in a cell.
+
+For scale data, @code{COUNT} and @code{TOTALN} are the same.
+
+For categorical data, @code{TOTALN} counts missing values in excluded
+categories, that is, user-missing values not in an explicit category
+list on @code{CATEGORIES} (@pxref{CTABLES Per-Variable Category
+Options}), or user-missing values excluded because
+@code{MISSING=EXCLUDE} is in effect on @code{CATEGORIES}, or
+system-missing values. @code{COUNT} does not count these.
@item @code{VALIDN} (``Valid N'')
-The sum of valid count weights.
+The sum of valid count weights in included categories.
+
+@code{VALIDN} does not count missing values regardless of whether they
+are in included categories via @code{CATEGORIES}. @code{VALIDN} does
+not count valid values that are in excluded categories.
@item @code{VARIANCE} (``Variance'')
The variance.
@table @asis
@item Explicit categories.
-@anchor{CTABLE Explicit Category List}
+@anchor{CTABLES Explicit Category List}
To explicitly specify categories to include, list the categories
within square brackets in the desired sort order. Use spaces or
commas to separate values. Categories not covered by the list are
With @code{SMISSING=VARIABLE}, which is the default, missing values
are excluded on a variable-by-variable basis. With
-@code{SMISSING=LISTWISE}, when scalar variables are stacked, a missing
-value for any of the scalar variables causes the case to be excluded
-for all of them.
+@code{SMISSING=LISTWISE}, when stacked scalar variables are nested
+together with a categorical variable, a missing value for any of the
+scalar variables causes the case to be excluded for all of them.
+
+As an example, consider the following dataset, in which @samp{x} is a
+categorical variable and @samp{y} and @samp{z} are scale:
+
+@psppoutput{ctables18}
+
+@noindent
+With the default missing-value treatment, @samp{x}'s mean is 20, based
+on the values 10, 20, and 30, and @samp{y}'s mean is 50, based on 40,
+50, and 60:
+
+@example
+CTABLES /TABLE (y + z) > x.
+@end example
+@psppoutput{ctables19}
+
+@noindent
+By adding @code{SMISSING=LISTWISE}, only cases where @samp{y} and
+@samp{z} are both non-missing are considered, so @samp{x}'s mean
+becomes 15, as the average of 10 and 20, and @samp{y}'s mean becomes
+55, the average of 50 and 60:
+
+@example
+CTABLES /SMISSING LISTWISE /TABLE (y + z) > x.
+@end example
+@psppoutput{ctables20}
+
+@noindent
+Even with @code{SMISSING=LISTWISE}, if @samp{y} and @samp{z} are
+separately nested with @samp{x}, instead of using a single @samp{>}
+operator, missing values revert to being considered on a
+variable-by-variable basis:
+
+@example
+CTABLES /SMISSING LISTWISE /TABLE (y > x) + (z > x).
+@end example
+@psppoutput{ctables21}
@node CTABLES Computed Categories
@subsection Computed Categories
categories created using arithmetic on categories obtained from the
data. The @code{PCOMPUTE} subcommand defines computed categories,
which can then be used in two places: on @code{CATEGORIES} within an
-explicit category list (@pxref{CTABLE Explicit Category List}), and on
+explicit category list (@pxref{CTABLES Explicit Category List}), and on
the @code{PPROPERTIES} subcommand to define further properties for a
given postcompute.
@itemx MISSING
@itemx OTHERNM
These forms evaluate to the summary statistics for categories matching
-the given syntax, as described in previous sections (@pxref{CTABLE
+the given syntax, as described in previous sections (@pxref{CTABLES
Explicit Category List}). If more than one category matches, their
values are summed.
projects / pspp / blobdiff