[R-sig-ME] Problems with function ranef in lme4

[Manuel Spínola]

Dear list members,

I am trying the function ranef from package lme4 and I got the following 
error warning:

 > data(sleepstudy)
 > fm1 <- lmer(Reaction ~ Days + (Days|Subject), sleepstudy)
 > ranef(fm1)
Error en UseMethod("ranef") :
  no applicable method for 'ranef' applied to an object of class "mer"

What could be the problem?
Best,

Manuel

-- 
Manuel Spínola, Ph.D.
Instituto Internacional en Conservación y Manejo de Vida Silvestre
Universidad Nacional
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