Documentation error?

[Andreas J. Guelzow]

Hi

At http://www.gnu.org/software/pspp/manual/pspp_142.html#SEC14
it is stated:

|SAMPLE| is used to randomly sample a proportion of the cases in the 
active file. |SAMPLE| is temporary, affecting only the next procedure, 
unless that is a data transformation, such as |SELECT IF| or |RECODE|.

This seem to be incorrect (or at least not what PSPP 0.2.4 really does).

Executing the following code:

DATA LIST LIST /var.
BEGIN DATA
10
20
30
40
END DATA
SAMPLE 2 FROM 4.
DESCRIPTIVES /VARIABLES=var /STATISTICS=DEFAULT.
SAMPLE 2 FROM 4.
DESCRIPTIVES /VARIABLES=var /STATISTICS=DEFAULT.

should (if the documentation were correct) show the descriptive 
statistics for two samples of size 2. But the last sample is in fact of 
size 21 only.

Moreover, if we skip the second `SAMPLE' both descriptive statistics use 
the same sample of 2 records, rather than a sample of 2 and all records 
what would be expected if the `SAMPLE' command is only temporary.

Or do I misunderstand what the documentation is saying?

Andreas

--
Prof. Dr. Andreas J. Guelzow                    
Chair of Science
Concordia University College of Alberta
http://www.math.concordia.ab.ca/aguelzow