I think you really want a normality test. If that's what you want, you have more options than the three-sigma rule.
http://en.wikipedia.org/wiki/Normality_test Tom On Tue, May 31, 2011 at 12:31 PM, Bert Gunter <gunter.ber...@gene.com> wrote: > Folks: > > On Tue, May 31, 2011 at 8:48 AM, Petr PIKAL <petr.pi...@precheza.cz> wrote: >> Hi >> >> r-help-boun...@r-project.org napsal dne 28.05.2011 20:12:33: >> >>> "Salil Sharma" <sali...@gmail.com> >>> Odeslal: r-help-boun...@r-project.org >>> Dear Sir, >>> >>> >>> >>> I have data, coming from tests, consisting of 300 values. Is there a way >> in >>> R with which I can confirm this data to 68-95-99.8 rule or three-sigma >> rule? >>> >>> I need to look around percentile ranks and prediction intervals for this >>> data. I, however, used SixSigma package and used ss.ci() function, which >>> produced 95% confidence intervals. I still am not certain about >> percentile >>> ranks conforming to 68-95-99.7 rule for this data. >>> >> >> Not sure what you exactly want but you could look at function quantile. > > -- Nor am I, but ... >> >> Or you could compute confidence interval for mean by e.g. >> > > I'm pretty sure that this is NOT what he wants. > > -- Bert > > >>> mean.int >> function (x, p = 0.95) >> { >> x.na <- na.omit(x) >> mu <- mean(x.na) >> odch <- sd(x.na) >> l <- length(x.na) >> alfa <- (1 - p)/2 >> mu.d <- mu - qt(1 - alfa, l - 1) * odch/sqrt(l) >> mu.h <- mu + qt(1 - alfa, l - 1) * odch/sqrt(l) >> return(data.frame(mu.d, mu, mu.h)) >> } >> >> Regards >> Petr >> >> >>> >>> >>> Thanks and regards, >>> Salil Sharma >>> >>> >>> [[alternative HTML version deleted]] >>> >>> ______________________________________________ >>> 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. >> >> ______________________________________________ >> 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. >> > > > > -- > "Men by nature long to get on to the ultimate truths, and will often > be impatient with elementary studies or fight shy of them. If it were > possible to reach the ultimate truths without the elementary studies > usually prefixed to them, these would not be preparatory studies but > superfluous diversions." > > -- Maimonides (1135-1204) > > Bert Gunter > Genentech Nonclinical Biostatistics > > ______________________________________________ > 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. > ______________________________________________ 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.
