Hypothesis test
From: "Moustafa ElHousinie" <drhosini at hotmail.com> To: r-help at stat.math.ethz.ch Copies to: syed at saudionline.com.sa Subject: Re: [R] Hypothesis test Date sent: Sat, 07 Apr 2001 06:33:16 -0000
Dear colleague: Actually that is what is done. When using the z-test between proportions in two different groups, or using chi-squared to test the null hypothesis of equal proportions of two or more groups, the null hypothesis is that H0: p1=p2=p3.....=p
<<SNIP>>
Mostafa
Ahem. I believe this is not the question originally posed:
From: "syed gillani" <syed at saudionline.com.sa> To: <r-help at stat.math.ethz.ch> Subject: [R] Hypothesis test Date: Sat, 7 Apr 2001 06:11:42 +0300 Hello, Is it reasonable to run a test of significance regarding a proportion in a group versus that in the whole population? What kind of problems can one face in analysis?
That would seem to be: How do I test Ho: p = p0 for some fixed value of p0, given an observed proportion p-hat (based on a sample of size n)? Answer: Calculate a p-value directly from the binomial distribution B(n, p0) or, if min(n*p0, n*(1-p0)) is not too small, use the normal approximation based on z = (p-hat - p0) / sqrt(p0*(1-p0)/n) To that z you may or may not want to add a continuity correction, depending on your position on that particular issue. Both tests assume that n is small compared to the population size, are standard fare in intro textbooks, and easily calculated from R's command line. ---JRG John R. Gleason Syracuse University 430 Huntington Hall Voice: 315-443-3107 Syracuse, NY 13244-2340 USA FAX: 315-443-4085 PGP public key at keyservers -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-help-request at stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._