[R-sig-ME] logLik

[Daniel Ezra Johnson]

Hi,

This is from the help file for logLik():

> x <- 1:5
> lmx <- lm(x ~ 1)
> logLik(lmx)

log Lik.' -8.82756 (df=2)

Two questions:
1) doesn't the model lmx have one degree of freedom, not two?
2) how is this log-likelihood calculated?

If I have two nested linear models (say lm models, not worrying about
mixed models here), I know how to compare them using an F-test, but I
don't understand the difference (if there is one) between using an
F-test and using a likelihood-ratio test.

Thanks,
Dan