pooled variance = S2(e) = ((n1-1)*sd1**2 + (n2-1)*sd2**2)/(n1 + n2 - 2)

standard error of the difference = S(mean1-mean2) = sqrt(s2(e)*(1/n1 + 1/n2))

t (tradtional) = (mean1 - mean2) / S(mean1 - mean2)

Paul R. Swank, Ph.D. Professor, Developmental Pediatrics Director of Research, Center for Improving the Readiness of Children for Learning and Education (C.I.R.C.L.E.) Medical School UT Health Science Center at Houston

-----Original Message----- From: SAS(r) Discussion [mailto:SAS-L@LISTSERV.UGA.EDU] On Behalf Of jn mao Sent: Wednesday, June 28, 2006 11:02 AM To: SAS-L@LISTSERV.UGA.EDU Subject: t test code

Hello SAS-Ls,

Could anyone tell me how to write a SAS code for a simple two sample t-test with just mean and sd? I don't have original data but two group means and SDs. I need SAS output for these two group comparisons. Thanks much.

I have mean1, sd1, mean2 and sd2. Thanks much.

Jane

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