Gregory (Greg) L. Snow Ph.D.
Statistical Data Center
Intermountain Healthcare
greg.snow at imail.org
801.408.8111
> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
> project.org] On Behalf Of ANJAN PURKAYASTHA
> Sent: Thursday, January 22, 2009 9:52 AM
> To: r-help at r-project.org
> Subject: [R] quantile question
>
> Hi,
> A simple quantile question:
> I need to calculate the 95% and 5% quantiles (aka percentiles) for the
> following data:
> 67.12
> 64.51
> 62.06
> 55.45
> 51.41
> 43.78
> 10.74
> 10.14
>
> if I use the formula: 95% quantile point= 95 (8+1)/100, I get the
> 8.55th
> point as the 95% quantile. Which does not make too much sense as I have
> only
> 8 data points.
> The other option is to use (95*8)/100 = 7.6th data point (which can be
> found
> by interpolation between the 7th and 8th data points).
> Reportedly, the second formula is not too accurate. However in my case
> the
> first formula does not make much sense.
>
> Any advice?
>
> TIA,
> Anjan
>
> --
> =============================
> anjan purkayastha, phd
> bioinformatics analyst
> whitehead institute for biomedical research
> nine cambridge center
> cambridge, ma 02142
>
> purkayas [at] wi [dot] mit [dot] edu
> 703.740.6939
>
> [[alternative HTML version deleted]]
>
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