[R] Relation 1.5*IQR/Percentile in case of a normal Distribution

[Johannes Graumann]

On Saturday 14 August 2010 23:08:31 Peter Dalgaard wrote:
> Johannes Graumann wrote:
> > Hi,
> > 
> > can someone point me at material to understand how in
> > http://upload.wikimedia.org/wikipedia/commons/8/89/Boxplot_vs_PDF.png the
> > "fivenum"-corresponding percentages might be calculated?
> 
> Looks like a pretty straightforward application of pnorm() and qnorm().
> 
> pnorm(4*qnorm(.75), lower=F) # Q3 + 1.5 IQR = 4 Q3 since IQR = 2 Q3
> 
> [1] 0.003488302
> 
> gives the tail probabilities of .35%, and the rest is by definition.

Thanks a lot!

Joh
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