Enrico, prop.test is for testing proportions two at a time. If you want to test for differences between 4 proportions simultaneously (rather than two at a time), try a logistic regression model (from which you can get confidence intervals for each of your groups).
Cody Hamilton, PhD Staff Biostatistician Edwards Lifesciences "Salvatore Enrico Indiogine" <[EMAIL PROTECTED] To .com> R-help@stat.math.ethz.ch Sent by: cc [EMAIL PROTECTED] at.math.ethz.ch Subject [R] confidence intervals on multiple comparisons 05/13/2007 10:51 AM Greetings! I am using prop.test to compare 4 proportions to find out whether they are equal. According to the help function you can not have confidence intervals if you compare more than 2 proportions. I need to find an effect size or confidence interval for these proportions. Any suggestions? Enrico -- Enrico Indiogine Mathematics Education Texas A&M University [EMAIL PROTECTED] ______________________________________________ R-help@stat.math.ethz.ch 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. ______________________________________________ R-help@stat.math.ethz.ch 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.