[R] yet another lmer question

From: Andrew Gelman <gelman_at_stat.columbia.edu>
Date: Sun 29 Jan 2006 - 04:09:56 EST


I've been trying to keep track with lmer, and now I have a couple of questions with the latest version of Matrix (0.995-4). I fit 2 very similar models, and the results are severely rounded in one case and rounded not at all in the other.

> y <- 1:10
> group <- rep (c(1,2), c(5,5))
> M1 <- lmer (y ~ 1 + (1 | group))
> coef(M1)
$group
  (Intercept)

1         3.1
2         7.9

> x <- rep (c(1,2), c(3,7))
> M2 <- lmer (y ~ 1 + x + (1 + x | group))
> coef(M2)

$group
  (Intercept) x
1 -0.755102 2.755102
2 0.616483 3.640738

I can't figure out why everything is rounded for the first model but not for the second. Also, mcmcsamp() works for M1 but not for M2:

> mcmcsamp(M1)

     (Intercept) log(sigma^2) log(grop.(In))
[1,]    9.099073    0.5711817       3.246981
attr(,"mcpar")
[1] 1 1 1
attr(,"class")
[1] "mcmc"

> mcmcsamp(M2)

Error: inconsistent degrees of freedom and dimension Error in t(.Call("mer_MCMCsamp", object, saveb, n, trans, PACKAGE = "Matrix")) :

        unable to find the argument 'x' in selecting a method for function 't'

-- 
Andrew Gelman
Professor, Department of Statistics
Professor, Department of Political Science
gelman@stat.columbia.edu
www.stat.columbia.edu/~gelman

Tues, Wed, Thurs:  
  Social Work Bldg (Amsterdam Ave at 122 St), Room 1016
  212-851-2142
Mon, Fri:
  International Affairs Bldg (Amsterdam Ave at 118 St), Room 711
  212-854-7075

Mailing address:
  1255 Amsterdam Ave, Room 1016
  Columbia University
  New York, NY 10027-5904
  212-851-2142
  (fax) 212-851-2164

______________________________________________
R-help@stat.math.ethz.ch mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
Received on Sun Jan 29 04:18:29 2006

This archive was generated by hypermail 2.1.8 : Fri 03 Mar 2006 - 03:42:14 EST