Dear R-Experts, I am trying to calculate the confidence intervals of the Goodman & Kruskal gamma statistics using bootstrap. There is no gamma function in the boot package. There is a gamma function in the base package, but it is the usual mathematical function.
So, I decide to try to calculate the confidence intervals using this site : http://www.statmethods.net/advstats/bootstrapping.html I get a "normal" warning message, but my R code is not working and I don't understand where my mistake(s) is (are). Here is the reproducible example with imaginary/fake data. install.packages("ryouready") library(ryouready) a=c("satisfait", "pas satisfait", "tres satisfait","satisfait","tres satisfait","pas satisfait","satisfait","satisfait","tres satisfait","pas satisfait") b=c("grand", "petit", "petit", "grand", "petit", "grand", "grand", "petit", "petit", "grand") x=table(a,b) ord.gamma(x) # calculate Goodman & Kruskal gamma using bootstrap library(boot) GK <- function(formula, data, indices) { d <- data[indices,] # allows boot to select sample tab <- xtabs(formula, data=d) stat <- ord.gamma(tab) return(stat) } # bootstrapping with 2000 replications results <- boot(data=d, statistic=GK,R=2000) # view results results plot(results) # get 95% confidence interval boot.ci(results, type="all") Best Regards, thanks for your precious help! SV ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see 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.
