[R] Odp: Three sigma rule

[Petr PIKAL]

Hi

r-help-bounces at r-project.org napsal dne 28.05.2011 20:12:33:

> "Salil Sharma" <salil31 at gmail.com> 
> Odeslal: r-help-bounces at 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.

Or you could compute confidence interval for mean by e.g.

> 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]]
> 
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