[R] linear model: Test difference between coefficients and given values (t.test?)

[Katharina May]

Hi there,

I've got a question which is really trivial for sure but still I have
to ask as I'm not
making any progress solving it by myself (please be patient with an
undergraduate
student):

I've got a linear model (lm and lmer fitted with method="ML").
Now I want to compare the coefficients (slope, intercept, not the
random effects)
of both models with a given value (e.g. intercept=0.5, slope=2) to see
if the values
estimated with the models are significantly different from the given values.

I heard about t.test, but I'm sorry to say that I'm not quite
understanding what I have
to provide as arguments.

I would be more than happy if somebody can point out an example similar to the
comparison I have to do...

Thanks,

         Katharina