[R] function to determine to which class/category a value belongs to?

[David Winsemius]

You might want to experiment with:

  ql <- cut( fam$I[fam$I>0], breaks =  quantile( fam$I[fam$I>0],  
type=1) , right=FALSE)
  levels(ql) <- c("1stQ","2ndQ","3rdQ","4thQ")
  ql


cut() returns a factor. If you accept the default for the right  
parameter in cut, you will be pulling your hair out when dealig with a  
discrete variable.

On Jun 17, 2009, at 6:24 PM, Germán Bonilla wrote:

> Hi all,
>
> I've got a simple contingency table produced with table(), and the  
> upper and
> lower quartiles (quantile25 and quantile75) for the same dataset.
> Is there a function that tells me in which category does the value  
> of the
> quartile falls into?

I cannot quite parse this sentence. See if the example gives a  
meaningful result with your data, and read the help pages for quantile.

>
> for example:
>
> tabsp <- table(fam$I[fam$I>0])
>
> 1 3 6
> 6 1 1
>
> and for the cumulative frequency distribution
>
> tabcum <- cumsum(tabsp)
>
> 1 3 6
> 6 7 8
>
> so, If my lower quartile is "2", I can visually determine that it  
> falls into
> class/category "1" with 6 observations.  Is there a function that  
> performs
> this determination?
>
> Thanks.
>
> Germán Bonilla
> I. Ecol. UNAM
>
> 	[[alternative HTML version deleted]]
>
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David Winsemius, MD
Heritage Laboratories
West Hartford, CT