Other way around. If the sample size is greater than about 1/10 of the total N, the confidence interval becomes smaller. If we sample the entire populaiton, the CI is +/- 0. (assuming the measurement was precise, too:)
Jay Fred Ettish wrote: > "Jerry Dallal" <[EMAIL PROTECTED]> wrote in message > news:[EMAIL PROTECTED] > > Fred Ettish wrote: > > > > > > 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 > > > > It doesn't. When the sample size is, say, less than 10% of the > > population size. The uncertainty reflected in the CI is the > > uncertainty of the measuring instrument, that is, the point estimate > > from the sample. > > So if a sample of 15,000 came from a population of 15,001 one couldn't be > confident about a narrower interval than if it came from a population of > 10^10? > > . > . > ================================================================= > 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/ . =================================================================
