dredge function error - R package MuMln

Question

I have to do statistical analyses on a data set. I would like to create all the possible models and to test them with the dredge function but it doesn\'t work. Indeed, when

Answer 1

See ?dredge:

# Example from Burnham and Anderson (2002), page 100:
data(Cement)
options(na.action = "na.fail")   #  prevent fitting models to different datasets

fm1 <- lm(y ~ ., data = Cement)
dd <- dredge(fm1)

If you skip the second line, your described error pops up, as the models are fitted to different datasets (due to removal of NAs).