[R] Glm and random effects

[Jorge Cornejo Donoso]

Hi, I'm traing to use the GLM to find tendences on my data.

E.G.
Data.frame: MyData
Len Zone	Year
12    1	2002	
21	1	2003
32	1	2004
32	2	2002
32	2	2003
31	2	2004
3	3	2002
4	3	2003
3	3	2004
32	4	2002
4	4	2003
5	4	2004


I want toi fing tendences on the len, if they change over the year (the
anova say yes), but I wan't to include the zone as a Random effect So, I
have something like this:
 SalGLM <- glm(MyData$Len ~ factor(MyData$year))	
 summary.glm(SalGLM)

But, I really don't know how to incorporate the zone as a random effect,
anybody could help please?

Thanks in advance