On Mon, 17 Nov 2008, Mariusz Doszy�^D wrote:
 > See the built-in functions pmean and psd.  See also the
function
 > package named "meansby" (written by Jack Lucchetti).  To find
 > this: /File/Function files/On server
 Thanks a lot Allin. I have also problems with setting sample
 range. When I try to change range of sample information that
 ending observation is invalid appears. 
Can you give an example of an attempt that fails, please?
Allin Cottrell