[R] Odp: Three sigma rule

[Thomas Levine]

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.berton at gene.com> wrote:
> Folks:
>
> On Tue, May 31, 2011 at 8:48 AM, Petr PIKAL <petr.pikal at precheza.cz> wrote:
>> 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.
>
> -- 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]]
>>>
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>>
>> ______________________________________________
>> R-help at r-project.org mailing list
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>> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
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>>
>
>
>
> --
> "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 at 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.
>