[R-sig-ME] confidence intervals in lmer
s0957429 at sms.ed.ac.uk
Sat Jan 22 20:57:25 CET 2011
Hi, I am trying to get the 95% confidence intervals for the coefficients
in the lmer model below.
I have tried to use the function ci(mod5) but get the following error
Error in .local(object, n, verbose, ...) :
Code for non-trivial theta_T not yet written
However, the function works when I alter my model as below:
I'm not sure this what this altered model means, (i.e. why are random
effects terms different, i'm still allowing both the intercept and the
slope of height to vary by group?) but the model output is different
from my original model. The coefficients are different and I seem to
now have eliminated any correlation between the slope and intercept.
Which I'm thinking was the reason why the ci function wouldn't work in
the first place?
Mod 6 output
Groups Name Variance Std.Dev.
species_site (Intercept) 2.32117 1.52354
species_site centre.log.height 0.47887 0.69200
Residual 0.10036 0.31679
Number of obs: 302, groups: species_site, 12
Estimate Std. Error t value
(Intercept) -0.47716 0.44829 -1.064
centre.log.dbh 1.68772 0.07536 22.396
centre.log.height 0.67887 0.24345 2.789
Correlation of Fixed Effects:
cntr.lg.hgh 0.028 -0.302
Any help in understanding whats going on would be great!
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