Error in anova(): objects must inherit from classes

Hello:

Let me rephrase my question to attract interest in the problem I'm having. When I appply anova() to two equations
estimated using glmmPQL, I get a complaint,

anova(fm1, fm2)

Error in anova.lme(fm1, fm2) : Objects must inherit from classes "gls",
"gnls" "lm","lmList", "lme","nlme","nlsList", or "nls"

The two equations I estimated are these:

fm1 <- glmmPQL(choice ~ day + stereotypy,

+                random = ~ 1 | bear, data = learning, family = binomial)

fm2 <- glmmPQL(choice ~ day + envir + stereotypy,

+                random = ~ 1 | bear, data = learning, family = binomial)

Individually, I get results from anova():

anova(fm1)

numDF denDF   F-value p-value
(Intercept)     1  2032   7.95709  0.0048
day             1  2032 213.98391  <.0001
stereotypy      1  2032   0.42810  0.5130

anova(fm2)

numDF denDF   F-value p-value
(Intercept)     1  2031   5.70343  0.0170
day             1  2031 213.21673  <.0001
envir           1  2031  12.50388  0.0004
stereotypy      1  2031   0.27256  0.6017

I did look through the archives but didn't finding anything relevant to my problem.

Hope someone can help.

ANDREW
____________________________
         _
platform i586-mandrake-linux-gnu
arch     i586
os       linux-gnu
system   i586, linux-gnu
status
major    2
minor    0.0
year     2004
month    10
day      04
language R

Andrew R. Criswell, Ph.D.
Graduate School, Bangkok University

mailto:andrew.c at bu.ac.th <http://email.bu.ac.th/src/compose.php?send_to=andrew.c%40bu.ac.th>
mailto:andrew at arcriswell.com <http://email.bu.ac.th/src/compose.php?send_to=andrew%40arcriswell.com>