[R] Help with multicomarisons after ANCOVA

[eesteves@ualg.pt]

Dear All,

I' ve used ANCOVA (through lm(Y~factor*x)) to study the influence/differences
between levels of factor upon the Y-x relationship. I found that both
intercepts and slopes differ among levels of the factor. I understand from the
results of summary(lm(Y~factor*x)) which of the intercepts/slopes per level
differ from "the reference level". I later used lm(Y~factor/(1+x)-1) to obtain
"explicit" coefficients per level.

My question is: Can I test for differences among all intercepts and /or slopes
per levels using simtest (from package multicomp) as summary
(simtest(Y~factor+x,type="tukey"))?

The outputs seem to contradict the results from the "explicit coefficients
approach"!

Thanks in advance,
Eduardo