On 07/09/2010 05:33 PM, Saeed Abu Nimeh wrote:
Is there a function similar to combine.levels ( in the Hmisc package)
that combines the levels of factors, but not based on their frequency.
Alternatively, I am looking into using the significance of the dummy
variables of factors based on their Pr(>|t|) value using the linear
model, then deleting the non-significant levels. Any other
suggestions?
Thanks,
Saeed
That is not a valid statistical procedure. You will not have the
correct d.f. in the final F test.
Frank
--
Frank E Harrell Jr Professor and Chairman School of Medicine
Department of Biostatistics Vanderbilt University
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