[R] urgent question about Lmer models

[Aline Andrey]

Dear r-help,

I have a question about the std error of a lmer model with library
(LmerTest).

I have 12 sites with 6 treatments over each site. I measured some response
variable (biomass_of_insects) (with a gaussian distribution).

I did :
library (LmerTest)
model<- lmer((biomass_of_insects) ~ as.factor(treatments) + (1 | sites))

However, the response of the model show always the same std error (see
below):

Fixed effects:
                       Estimate Std. Error      df t value Pr(>|t|)
(Intercept)             501.333     80.656  66.000   6.216 3.91e-08 ***
as.factor(treat)F       126.667    114.065  66.000   1.110    0.271
as.factor(treat)I        -8.333    114.065  66.000  -0.073    0.942
as.factor(treat)I+F1/3  -75.000    114.065  66.000  -0.658    0.513
as.factor(treat)I+F2/3   18.333    114.065  66.000   0.161    0.873
as.factor(treat)I+F3/3   15.917    114.065  66.000   0.140    0.889



Do you know why std.error is always the same ?

Thank you very much,

Aline

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