hanen <hanen.mastouri <at> yahoo.fr> writes: > > > hello; > firstly, my gratitude to all who help me to find a function that allows me > to add confidence interval to my graph. > in order to calculate the (1-alpha)th percentile of for exemple an > F(df1,df2) distribution i do like this: > v<-df(alpha,df1,df2) > percentile<-qf(v,df1,df2,alpha) > > if it is true please alert me , and if it is not what should do then? > > :handshake:
I think it's just qf(1-alpha,df1,df2) To use a well-known example: qnorm(0.975) = 1.959964 (in this case, for a two-tailed test, you need 1-alpha/2 , but F is one-tailed so that's no problem. Ben Bolker ______________________________________________ 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.
