Dear users,

I'll appreciate your help with this (hopefully) simple problem.

I have a model object which was fitted to inputs X1, X2, X3. Now, I'd like
to use this object to make predictions on a new data set where only X1 and
X2 are available (just use the estimated coefficients for these variables in
making predictions and ignoring the coefficient on X3). Here's my attempt
but, of course, didn't work.

#fit some linear model to random data

x=matrix(rnorm(100*3),100,3)
y=sample(1:2,100,replace=TRUE)
mydata <- data.frame(y,x)
mymodel <- lm(y ~ ns(X1, df=3) + X2 + X3, data=mydata)
summary(mymodel)

#create new data with 1 missing input

mynewdata <- data.frame(matrix(rnorm(100*2),100,2))
mypred <- predict(mymodel, mynewdata)
Thanks in advance for your help!

Axel.

	[[alternative HTML version deleted]]

