Hanna,
If you are interested in whether effect of time varies across individuals,
why don't you fit a model with the predictors (time*individual) as fixed
effects rather than random?
On Mon, Jun 6, 2016 at 10:57 AM, li li <hannah.hlx at gmail.com> wrote:
> Hi all,
> After fitting a random slope and random intercept model using lme
> function, I want
> to test whether each of the fixed slopes is equal to zero (The output of
> model is below).
> Can this be done (testing each individual slope) using multcomp package?
> Thanks much for the help.
> Hanna
>
> > summary(mod1)Linear mixed-effects model fit by REML
> Data: one
> AIC BIC logLik
> 304.4703 330.1879 -140.2352
>
> Random effects:
> Formula: ~1 + time | individual
> Structure: General positive-definite, Log-Cholesky parametrization
> StdDev Corr
> (Intercept) 0.2487869075 (Intr)
> time 0.0001841179 -0.056
> Residual 0.3718305953
>
> Variance function:
> Structure: Different standard deviations per stratum
> Formula: ~1 | method
> Parameter estimates:
> 3 1 2
> 1.00000 26.59750 24.74476
> Fixed effects: reponse ~ method * time
> Value Std.Error DF t-value p-value(Intercept)
> 96.65395 3.528586 57 27.391694 0.0000
> method2 1.17851 4.856026 57 0.242689 0.8091
> method3 5.87505 3.528617 57 1.664973 0.1014time
> 0.07010 0.250983 57 0.279301 0.7810
> method2:time -0.12616 0.360585 57 -0.349877 0.7277
> method3:time -0.08010 0.251105 57 -0.318999 0.7509
> Correlation:
> (Intr) methd2 methd3 time mthd2:
> method2 -0.726
> method3 -0.999 0.726
> time -0.779 0.566 0.779
> method2:time 0.542 -0.712 -0.542 -0.696
> method3:time 0.778 -0.566 -0.779 -0.999 0.696
>
> Standardized Within-Group Residuals:
> Min Q1 Med Q3 Max
> -2.67575293 -0.51633192 0.06742723 0.59706762 2.81061874
>
> Number of Observations: 69
> Number of Groups: 7 >
>
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>
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