I am trying to fit a non linear mixed effect model but I also want to do a post
hoc comparison.
My
data is binary and consist of recording mice track prints on plates
plates in plots that submited to one of 4 different treatments (fruits
and vegetation complexity manipulated for two levels each. The design
is random blocks repeated measures with presence or absence of track
prints as a response variable. Treatment is fixeed, time is fixed, and
block is a random effect. I would like to know how I could do a post
hoc comparison to see which months had a significant effect of an
specific treatment. I searche on Bates and Pinheiro book but they don't
have an example of it.
> names (kirk)
[1] "Obs"
"track" "time" "block" "treat" ##Obs is the track plate identity,
track is response variable, time is the month in which it was recorded
and treat is one of the four treatments.##
> mice <- lmer(track ~treat*time+(1|block), family=binomial, method =
> "PQL",data = kirk)
> mice
Generalized linear mixed model fit using PQL
Formula: track ~ treat * time + (1 | block)
Data: kirk
Family: binomial(logit link)
AIC BIC logLik deviance
956.9 1002 -469.4 938.9
Random effects:
Groups Name Variance Std.Dev.
block (Intercept) 0.58182 0.76277
number of obs: 1168, groups: block, 3
Estimated scale (compare to 1 ) 1.000414
Fixed effects:
Estimate Std. Error z value Pr(>|z|)
(Intercept) -1.39258 0.54124 -2.573 0.010084 *
treatFIVR -1.69691 0.53920 -3.147 0.001649 **
treatFRVI -0.86542 0.49603 -1.745 0.081039 .
treatFRVR -1.54753 0.59766 -2.589 0.009617 **
time -0.05365 0.08459 -0.634 0.525957
treatFIVR:time 0.43627 0.13169 3.313 0.000924 ***
treatFRVI:time 0.23028 0.12637 1.822 0.068418 .
treatFRVR:time 0.16126 0.15067 1.070 0.284502
---
Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1
Correlation of Fixed Effects:
(Intr) trFIVR trFRVI trFRVR time tFIVR: tFRVI:
treatFIVR -0.327
treatFRVI -0.359 0.359
treatFRVR -0.297 0.298 0.324
time -0.506 0.503 0.548 0.454
tretFIVR:tm 0.319 -0.906 -0.351 -0.292 -0.640
tretFRVI:tm 0.336 -0.337 -0.896 -0.304 -0.668 0.429
tretFRVR:tm 0.283 -0.282 -0.307 -0.899 -0.561 0.359 0.375
thank you for your help
Humberto Dutra
==========================================================
'Discipline - Success doesn't just happen. You have to be intentional about it,
and that takes discipline.' - John Maxwell
Humberto Dutra
==========================================================
'Discipline - Success doesn't just happen. You have to be intentional about it,
and that takes discipline.' - John Maxwell
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