You are right, it is not symmetric, absolutely. The difference is small, except near the extremes, and I believe for low n.
My ref. is a 1963 text and the equations are not simple. And they are still approximations. Later I can provide them, but not this moment. :( If you want the full & compelte thing, you will have to work through using a binomial distribution and eqs. for same. Jay sleszyk wrote: > U�ytkownik "Fred Ettish" <[EMAIL PROTECTED]> napisa3 w wiadomo�ci > news:[EMAIL PROTECTED] > > A recent poll by the Pew Group of 15000 Muslims world wide found 71% > support > > Bin Laden. Looking at my textbook the formula for a population proportion > > is: > > > > p +/- Z * SQRT ( p(1-p)/n ) > > > > Ok simple enough, but my question is doesn't the population size affect > the > > confidence interval? How does the fact that their are 2000000000 affect > the > > interval? > > > > Thanks > > > > > > I have another question about the proportion confidence interval: > > With the above formula one can calcute the symmetrical interval, which is ok > as long as the proportion is not too close to 0 or 1. > However, from what I've heard the "real" CI is always asymmetrical (well, > maybe except for p=0,5). > > Does anybody know how to calculate an asymmetrical CI for a proportion? > I've been looking for an answer on the web some time ago and couldn't find > it. > > Thanks, > Peter. > > -- > Serwis Usenet w portalu Gazeta.pl -> http://www.gazeta.pl/usenet/ > . > . > ================================================================= > Instructions for joining and leaving this list, remarks about the > problem of INAPPROPRIATE MESSAGES, and archives are available at: > . http://jse.stat.ncsu.edu/ . > ================================================================= -- Jay Warner Principal Scientist Warner Consulting, Inc. 4444 North Green Bay Road Racine, WI 53404-1216 USA Ph: (262) 634-9100 FAX: (262) 681-1133 email: [EMAIL PROTECTED] web: http://www.a2q.com The A2Q Method (tm) -- What do you want to improve today? . . ================================================================= Instructions for joining and leaving this list, remarks about the problem of INAPPROPRIATE MESSAGES, and archives are available at: . http://jse.stat.ncsu.edu/ . =================================================================
