It might help to look at the documentation. Typing ?prop.test
on the command line. That would reveal various items of interest, including a section labeled "Details". A close reading of that section turns up the explanation: "The confidence interval is computed by inverting the score test." There are also journal references given. albyn On Wed, Apr 03, 2013 at 06:17:56PM -0400, Sarah Goslee wrote: > One of the joys of R is that it's open source: you can read the code > for prop.test yourself and see what's happening. > > In this case, simply typing > prop.test > at the command line will provide it, although without comments. > > Sarah > > > > On Wed, Apr 3, 2013 at 6:10 PM, David Arnold <dwarnol...@suddenlink.net> > wrote: > > Hi, > > > > This code: > > > > n=40 > > x=17 > > phat=x/n > > SE=sqrt(phat*(1-phat)/n) > > zstar=qnorm(0.995) > > E=zstar*SE > > phat+c(-E,E) > > > > Gives this result: > > > > [1] 0.2236668 0.6263332 > > > > The TI Graphing calculator gives the same result. > > > > Whereas this test: > > > > prop.test(x,n,conf.level=0.99,correct=FALSE) > > > > Give this result: > > > > 0.2489036 0.6224374 > > > > I'm wondering why there is a difference. > > > > D. > > > > > > -- > Sarah Goslee > http://www.functionaldiversity.org > > ______________________________________________ > R-help@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. > -- Albyn Jones Reed College jo...@reed.edu ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
