On Mon, 10 Sep 2012, Filipa J. wrote:
> Dear R users,
>
> I want to apply zero inflated models with continuous and categorical
> variables and I used pscl package from R and the zeroinf() function. My
> question are the follow:
>
> a) The value of fitted.values is mu or (1-p)*mu? where p is the
> probability of zero came form a zero point mass

See vignette("countreg", package = "pscl"), especially
Appendix C.
The default predict(..., type = "response") and fitted(...) both
compute
the expected value Equation (8). This corresponds to your (1-p)*mu but
uses a different notation.
> b) If mu is zero, how do i know if it is a zero from the zero point mass
> or from the count process?

You can inspect all component: Your "mu" ("exp(x'b)" in
the notation of
the paper) can be computed with predict(..., type = "count") and
"p" ("pi"
in the paper) with predict(..., type = "zero").
Best,
Z