Any suggestion from you are welcome.

Thanks!

my best

---------- Forwarded message ----------
From: Lao Meng <laomeng.3@gmail.com>
Date: 2011/8/3
Subject: Re: [R-sig-ME] question about linear mixed model
To: Yuan-Ye Zhang <zhangyuanye0706@gmail.com>


Hi Yuan-Ye.
I've looked up for some papers on glht of multiple comparison.
Maybe glht compares the MEAN of each level of the group(in your example: the
MEAN of G1,G2,G3,G4).
In that case,maybe I can do it via ANOVA,and compare whether the result of
ANOVA is the same with glht(mod, linfct=mcp(GROUP="Tukey")).

I use the raw dependent  value, and use anova to do multiple comparison,but
the result is different from :glht(mod, linfct=mcp(GROUP="Tukey"))
Also,the result of predict value is different from above.


So,I'm confused which kind of MEAN is compared?

Thanks



2011/7/28 Yuan-Ye Zhang <zhangyuanye0706@gmail.com>

> I wonder how many levels in your GROUP factor.
> What is your specific model to put into the glht function?
> Usually you get one intercept three slopes, if GROUP has four levels.
>
> Take for example
> mod<-lmer(Y~GROUP+(1|family))   GROUP has four levels, G1, G2, G3, G4
> glht(mod, linfct=mcp(GROUP="Tukey"))
> The null hypotheses for the multicomp are
> G1==G2
> G1==G3
> G1==G4
> G2==G3
> G2==G4
> G3==G4
>
> The results makes no differences if -mod<-lmer(Y~0+GROUP+(1|family)) .
> But I am not sure the if you includes a interaction in the model.
>
>
> yuanye
>
>
> 2011/7/28 Lao Meng <laomeng.3@gmail.com>
>
>> Thanks Yuan.
>> Here's another question:
>> What's kind of difference does glht tests?
>> In other words,
>> If I get 4 intercepts and 4 slopes for all levels of GROUP,then glht tests
>> for the difference of the 4 intercepts or 4 slopes,or something else?
>>
>> Thanks.
>>
>>
>> 2011/7/19 Yuan-Ye Zhang <zhangyuanye0706@gmail.com>
>>
>>> Hi,
>>>
>>> 1. Maybe you could try model<- glmmPQL(log10(CD4) ~ time +
>>> (0+factor(group))+ time:factor(group), random = ~time|id).
>>> 0+ some times means that you do NOT fit a intercept, but fit each level a
>>> slope.
>>>
>>> 2. Maybe you could try
>>> library(multcomp),
>>> glht(model, linfct=mcp(fgroup="Tukey"))
>>> fgroup<-factor(group).
>>> The glht function work for "lmer" or "mer", but I am not sure whether it
>>> will help in your case.
>>>
>>> I hope it may help a bit.
>>> best,
>>> Yuanye
>>>
>>>
>>> 2011/7/19 Lao Meng <laomeng.3@gmail.com>
>>>
>>>> Hi all:
>>>> I have a question about linear mixed model.
>>>>
>>>> my linear mixed model with randomized slope and intercept with
>>>> interaction
>>>> of time and group(g1,g2,g3):
>>>> model<- glmmPQL(log10(CD4) ~ time + factor(group)+ time:factor(group),
>>>> random = ~time|id)
>>>>
>>>> What I get is only the main and interaction of time and group.My
>>>> question
>>>> is:
>>>>
>>>> 1. How can I get the g1,g2,g3's slope respectively?In other words,how
>>>> can I
>>>> get the slope of g1,the slope of g2,and the slope of g3?
>>>>
>>>> 2.How can I pair-wise compare the 3 slopes of g1,g2,g3?
>>>>
>>>>
>>>>
>>>> Thanks a lot!
>>>>
>>>>
>>>> My best
>>>>
>>>>        [[alternative HTML version deleted]]
>>>>
>>>> _______________________________________________
>>>> R-sig-mixed-models@r-project.org mailing list
>>>> https://stat.ethz.ch/mailman/listinfo/r-sig-mixed-models
>>>>
>>>
>>>
>>
>

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