[R] Extract random part of summary nlme

[Rense Nieuwenhuis]

Dear helpers,

I'm estimating multilevel regression models, using the lme-function  
from the nlme-package. Let's say that I estimated a model and stored  
it inside the object named 'model'. The summary of that model is  
shown below:

Using summary(model)$tTable , I receive the following output:

 > summary(model)$tTable
                     Value  Std.Error   DF     t-value       p-value
(Intercept)    0.23268607 0.09350662 3990   2.4884449  1.287080e-02
sexM          -0.15338225 0.03169762 3990  -4.8389206  1.354802e-06
standLRT       0.38593558 0.01677195 3990  23.0107762 4.005182e-110
vrmid 50%      0.07606394 0.09389376   61   0.8101064  4.210281e-01
vrtop 25%      0.24561327 0.10483374   61   2.3428838  2.241317e-02
intakemid 50% -0.41469716 0.03177240 3990 -13.0521199  3.698344e-38
intaketop 25% -0.75920783 0.05357980 3990 -14.1696648  1.666780e-44
typeSngl       0.15680532 0.07173835   61   2.1857949  3.267903e-02


All looks fine to me. The output above is simply  a section from the  
full summary shown below. Now, I want to extract from the summary (or  
the full model) the part stating the random parameters. More  
specifically, I want to extract from the summary the following:

(Intercept) 0.2869401 (Intr)
typeSngl    0.2791040 -0.617
Residual    0.7302233

How could this be done?

Thanks for the effort,

Rense Nieuwenhuis








Linear mixed-effects model fit by REML
  Data: Exam
       AIC      BIC   logLik
   9158.56 9234.241 -4567.28

Random effects:
  Formula: ~type | school
  Structure: General positive-definite, Log-Cholesky parametrization
             StdDev    Corr
(Intercept) 0.2869401 (Intr)
typeSngl    0.2791040 -0.617
Residual    0.7302233

Fixed effects: normexam ~ sex + standLRT + vr + intake + type
                    Value  Std.Error   DF    t-value p-value
(Intercept)    0.2326861 0.09350662 3990   2.488445  0.0129
sexM          -0.1533822 0.03169762 3990  -4.838921  0.0000
standLRT       0.3859356 0.01677195 3990  23.010776  0.0000
vrmid 50%      0.0760639 0.09389376   61   0.810106  0.4210
vrtop 25%      0.2456133 0.10483374   61   2.342884  0.0224
intakemid 50% -0.4146972 0.03177240 3990 -13.052120  0.0000
intaketop 25% -0.7592078 0.05357980 3990 -14.169665  0.0000
typeSngl       0.1568053 0.07173835   61   2.185795  0.0327
  Correlation:
               (Intr) sexM   stnLRT vrm50% vrt25% int50% int25%
sexM          -0.201
standLRT      -0.125  0.028
vrmid 50%     -0.742  0.028 -0.035
vrtop 25%     -0.652  0.051 -0.065  0.649
intakemid 50% -0.246 -0.011  0.541 -0.002  0.007
intaketop 25% -0.218 -0.018  0.676  0.014  0.013  0.660
typeSngl      -0.421  0.080  0.007  0.033 -0.027 -0.001  0.001

Standardized Within-Group Residuals:
         Min          Q1         Med          Q3         Max
-3.59074329 -0.63776965  0.03829878  0.67303837  3.33952680

Number of Observations: 4059
Number of Groups: 65