[R] lme parameterization question

[Christian Ritz]

Hi,

try something like:

lme(y~w,random=list(~1|year,~1+w|site))

Christian

----- Original Message ----- 
From: "John Fieberg" <John.Fieberg at dnr.state.mn.us>
To: <R-help at stat.math.ethz.ch>
Sent: Wednesday, April 02, 2003 10:36 PM
Subject: [R] lme parameterization question


> Hi,
> 
> I am trying to parameterize the following mixed model (following Piepho
> and Ogutu 2002), to test for a trend over time, using multiple sites:
> 
> y[ij]=mu+b[j]+a[i]+w[j]*(beta +t[i])+c[ij]
> 
> where:
> y[ij]= a response variable at site i and year j
> mu = fixed intercept
> Beta=fixed slope
> w[j]=constant representing the jth year (covariate) 
> b[j]=random effect of jth year, iid N(0,sigma2[b])
> a[i]=random effect of the ith site, iid N(0, sigma2[a])
> t[i]=random effect of ith site, iid N(0, sigma2[t])
> c[ij]=random error associated with ith site and jth year