RE: [R] factors in multinom function (nnet)

From: <>
Date: Wed 13 Apr 2005 - 09:57:56 EST


I have a couple of remarks to make, not all of which you might find immediately helpful, I regret to say.

Bill Venables.

-----Original Message-----
[] On Behalf Of Alexandre Brito Sent: Wednesday, 13 April 2005 8:20 AM
Subject: [R] factors in multinom function (nnet)

Dear All:

I am interested in multinomial logit models (function multinon, library nnet) but I'm having troubles in choose whether to define the predictors as factors or not.

I had posted earlier this example (thanks for the reply ronggui):

worms <- data.frame(year = rep(2000:2004, c(3,3,3,3,3)),

				age = rep(1:3, 5), 
	mud = c(2,5,0,8,7,7,5,9,14,12,8,7,5,13,11),
	sand = c(4,7,13,4,14,13,20,17,15,23,20,9,35,27,18), 
	rocks = c(2,6,7,9,3,2,2,10,5,19,13,17,11,20,29))

k <- as.matrix(worms[,3:5])

(mud, sand and rocks are factors; age and year are predictors)

Now there are several possibilities:

m1 <- multinom(k ~ year+age, data = worms)
m2 <- multinom(k ~ factor(year)+age, data = worms)
m3 <- multinom(k ~ year+factor(age), data = worms)
m4 <- multinom(k ~ factor(year)+factor(age), data = worms)
m5 <- multinom(k ~ year:age, data = worms)
m6 <- multinom(k ~ year*age, data = worms)
m7 <- multinom(k ~ factor(year):age, data=worms)
m8 <- multinom(k ~ year:factor(age), data=worms) 

and so on.

I am far from an expert on this, and I would like to learn more about the utilization of multinom function in R and the kind of doubts I described above. So I hope that someone can recommend me some references in this matter (internet, books...) if any is available.

Thanks in advance, best wishes

Alexandre mailing list PLEASE do read the posting guide! mailing list PLEASE do read the posting guide! Received on Wed Apr 13 10:05:41 2005

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