When I select a sample using > *Restrict, based in criterion *and then > *Use
dummy variable* all works fine, and I get the appropriate sub-set. When I
then select > *Random sub-sample* from this subset, everything is fine as
long as the number selected is less than the number of items that were
selected on the first call.
However, there is a misleading message *Number of observations to select
(max x)*, where x is greater than the number of observations that were
selected on the first call. Furthermore, if I specify a number larger than
the number of obs that were selected, it executes the specified x. However,
on occasions I do get the message *Invalid number of cases*. If I re-enter
the same x then it goes through. It appears there's a problem in trapping
this. Thanks.
*"In God we trust, all others bring data."*