[R] contrast reference level

[Peter Dalgaard]

array chip <arrayprofile at yahoo.com> writes:

> suppose I have a factor with 4 levels:
> 'a','b','c','d'. I would like to do analysis of
> variance using aov() with the factor as independent
> variable. How can I specify the level "b" as the
> reference level just like the level "a" would be the
> reference level if using contr.treatment as the
> contrast?

relevel() should do just that.

-- 
   O__  ---- Peter Dalgaard             Blegdamsvej 3  
  c/ /'_ --- Dept. of Biostatistics     2200 Cph. N   
 (*) \(*) -- University of Copenhagen   Denmark      Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk)             FAX: (+45) 35327907