[R] descretizing xy data

Erik Iverson iverson at biostat.wisc.edu
Mon Nov 3 19:40:15 CET 2008


Jon -

Jon A wrote:
> Hello,
> I have a dataset with a continuous independent variable (fish length, range:
> 30-150 mm) and a binary response (foraging success, 0 or 1). I want to
> discretize fish length into 5 mm bins and give the proportion of individuals
> who successfully foraged in each each size bin. I have used the cut function
> to discretize the length values into my desired bins, but I can't figure out
> how to manipulate my response data in terms of the levels I've created. Any
> advice on how to achieve my task?

You don't give example data, but would something like:

df ## your data frame
df$flcat <- cut(...) ## make categorical variable

## install package catspec from CRAN
library(catspec)
dftab <- table(df$flcat, df$success)
ctab(dftab) ## see ?ctab for options about row/column proportions

Hope that helps.



> 
> Thanks in advance.
> 
>



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