|
Statistical modelling
Comparison of the RAM_ID and EWE_ID
variance components with their standard errors indicates that the
variance component for ewes (1.457) is highly significant (component
> 5 times its standard error) but that for ram (0.067) is not
(component less than its standard error).
This, therefore, shows how,
especially with the ewe component included, the mixed model utilises
more of the information contained within the data than the model without
the ram and ewe components.
|
|
**Estimated Variance Components **
| Random
term |
Component |
S.e. |
| RAM_ID |
0.067 |
0.089 |
| EWE_ID |
1.457 |
0.283 |
***
Residual variance model ***
|
Parameter
|
Estimate
|
S.e.
|
|
Sigma2
|
3.427
|
0.266
|
**Approximate stratum variances ***
| |
|
Effective
d.f.
|
| RAM_ID |
4.733
|
57.66
|
| EWE_ID |
6.490
|
297.74
|
| *units* |
3.427
|
332.60
|
* Matrix of
coefficients of components for each stratum
| RAM_ID |
10.31
|
0.42
|
1.00
|
| EWE_ID |
0.00
|
2.10
|
1.00
|
| *units* |
0.00
|
0.00
|
1.00
|
*** Deviance: -2*Log-Likelihood ***
| Deviance |
d.f. |
| 1817.10 |
685 |
***
Wald tests for fixed effects ***
| Fixed
term |
Wald
statistic |
d.f.
|
Wald/d.f.
|
Chi-sq
prob
|
| *
Sequentially adding terms to fixed model |
| YEAR |
230.32
|
5
|
46.06
|
<0.001
|
| SEX |
9.66
|
1
|
9.66
|
0.002
|
| AGEWEAN |
63.84
|
1
|
63.84
|
<0.001
|
| DL |
30.44
|
1
|
30.44
|
<0.001
|
| DQ |
78.41
|
1
|
78.41
|
<0.001
|
| RAM_BRD |
6.64
|
1
|
6.64
|
0.010
|
| EWE_BRD |
2.91
|
1
|
2.91
|
0.088
|
|
|
