Date:         Tue, 31 Aug 2004 10:26:15 -0400
Reply-To:     Lu Liu <Lu.Liu@TALBOTS.COM>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         Lu Liu <Lu.Liu@TALBOTS.COM>
Subject:      Random Sampling
Content-Type: text/plain; charset="iso-8859-1"

Hi,

I have a statistical question regarding random sampling.  I have two pieces
of data: e-mail and customer ID.  After I sorted e-mails in alphabetical
order, I took the first 10,000 as sample group 1 and the second 10,000 as
sample group 2.  After I examined the frequency of the customer ID by
breaking down the ID into 10 ranges, the customer ID  frequency of the 2
samples is very similar to the entire population.  Can I say the 2 samples
are random samples?  I have a feeling that it is not, but can anyone provide
some explanations why this could be biased?

Thank you,
Lu