From rmjohnston at mac.com  Tue Oct 31 02:50:09 2006
From: rmjohnston at mac.com (rmjohnston at mac.com)
Date: Tue, 31 Oct 2006 02:50:09 +0100 (CET)
Subject: [Rd] Confidence interval calculation in prop.test (PR#9325)
Message-ID: <20061031015009.7A7903F006@slim.kubism.ku.dk>

Full_Name: Richard Johnston
Version: 2.4.0
OS: OS X
Submission from: (NULL) (69.169.0.241)


The confidence interval calculation for prop.test appears incorrect when
alternative="greater" .  The upper limit is always set to 1.0000.  The lower
limit appears to be correct.

> total=c(250,250)
> success=c(55,31)
> prop.test(success,total,alternative="greater",correct=TRUE)

	2-sample test for equality of proportions with continuity correction

data:  success out of total 
X-squared = 7.4289, df = 1, p-value = 0.003209
alternative hypothesis: greater 
95 percent confidence interval:
 0.03693065 1.00000000 
sample estimates:
prop 1 prop 2 
 0.220  0.124




[Rd] Confidence interval calculation in prop.test (PR#9325)
rmjohnston at mac.com