[R] stepAIC error

[Ben Bolker]

labbig <lkaimaka <at> windowslive.com> writes:

> 
> i am trying to run stepwise regression for two models(lower,upper),
> family=gamma
> and i get the same error despite the models i use.
> 
> Error in UseMethod("extractAIC") : 
>   no applicable method for 'extractAIC' applied to an object of class
> "formula"
> In addition: Warning message:
> In nobs.default(object, use.fallback = TRUE) :
>   no 'nobs' method is available
> 

  A reproducible example would definitely help.

  The "no 'nobs' method is available" warning is a clue that you
may be using an older version of R (I believe 'nobs' was introduced
in version 2.13).
 
  If you possibly can, update to the latest version of R and
post a reproducible example.

  Ben Bolker