update documentation for descriptives

diff --git a/rust/doc/src/commands/descriptives.md b/rust/doc/src/commands/descriptives.md
index 6585fc73e0ab1dd7719e83c3e0c37f04e41d4504..8941437f7abccee45a3109a34aaf73f086475619 100644 (file)
--- a/rust/doc/src/commands/descriptives.md
+++ b/rust/doc/src/commands/descriptives.md
@@ -42,9 +42,14 @@ the names `ZSC000` through `ZSC999`, `STDZ00` through `STDZ09`,
 `ZZZZ00` through `ZZZZ09`, `ZQZQ00` through `ZQZQ09`, in that order.
 Z-score variable names may also be specified explicitly on `VARIABLES`
 in the variable list by enclosing them in parentheses after each
-variable.  When Z scores are calculated, PSPP ignores
-[`TEMPORARY`](temporary.md), treating temporary transformations as
-permanent.
+variable.
+
+With [`TEMPORARY`](temporary.md), Z scores are computed on the final
+values of the variables following the temporary transformations, but
+they are included in the permanent cases preceding
+[`TEMPORARY`](temporary.md).  When a temporary [`SELECT
+IF`](select-if.md) deletes a case or a temporary [`FILTER`](filter.md)
+filters it out, its Z score will be the system-missing value.
 
 The `STATISTICS` subcommand specifies the statistics to be displayed: