On Thu, Jul 8, 2010 at 3:14 PM, Addi Wei <addiwei@gmail.com> wrote:

>
> Hopefully simple question:  What is the best way to name, and treat factor
> columns for data that has lots of columns?
>
> This is my column list:
> id pID50 D.1 D.2 D.3 D.4 D.5 , etc. all the way to D.185
>
It would be much better to use a factor and let R itself generate the set of
dummy variables.
Choose a useful name.  For example if D stands for Dose, then use something
like

micetitletest$Dose <- factor(micetitletest$dose.values)

miceD <- plsr(pID50 ~ Dose, ncomp=10, data = micetitletest)

Read about factors in the online An Introduction to R distributed as part of
R.

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