Date:         Sun, 16 Nov 2008 16:10:44 -0800
Reply-To:     dfisher@csulb.edu
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         "Dennis G. Fisher, Ph.D." <dfisher@CSULB.EDU>
Organization: California State University, Long Beach
Subject:      Re: Urgent help with power related for binomial proportion
Comments: To: Sophia Tong <sophiDT@HOTMAIL.COM>
In-Reply-To:  <200811162315.mAGBmJKU003090@malibu.cc.uga.edu>
Content-Type: text/plain; charset="us-ascii"

Sophia,
Usually the value of P2 is a substantive decision.  If you put in the values
of P1 and P2, then the software will calculate delta for you.  If you have
SAS 9.2 then you can use Power and sample size application.  If you have 9.1
then you might want to consider the analyst application in SAS that I find
to be easier to use than the alternative of proc power which you can also
use.  Good luck.
Dennis

Dennis G. Fisher, Ph.D.
Professor and Director
Center for Behavioral Research and Services
California State University, Long Beach
1090 Atlantic Avenue
Long Beach, CA 90813
tel: 562-495-2330 x121
fax: 562-983-1421

-----Original Message-----
From: SAS(r) Discussion [mailto:SAS-L@LISTSERV.UGA.EDU] On Behalf Of Sophia
Tong
Sent: Sunday, November 16, 2008 3:16 PM
To: SAS-L@LISTSERV.UGA.EDU
Subject: Urgent help with power related for binomial proportion

Dear SAS -L listers,

I am trying to calculate minimum detectable difference in a proposed study
to cpmare with historical data. The sample size, proportion of historical
data are known (n1 and P1 are know known). Power and Alpha are arbitarily
decided as 0.8 and 0.025, sample size was also proposed for different
numbers ( so, n2, beta and alpha are all known). I need find delta.

I was trying to derive delta from sample size formular in a textbook and
give it up after finding it's beyond my knowledge.

Does anyone know how to do it in SAS, will PROC POWER do it? Or any formular
people have already figured it out?
My deadline is tomorow, you help is greatly appreciated.

Thanks

Sophia