Table 7.
Simulated parameters | Estimated parameter values
|
σ | r2 | ||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Genetic main effects (G)
|
Environmental effects (E) and G × E
|
||||||||||||||||||||
Homozygous
|
Heterogygous
|
Epistatic
|
E | Homozygous
|
Heterozyous
|
Epistatic
|
|||||||||||||||
dA | dB | hA | hB | iAB | jAB | jBA | lAB | βm | βdA | βdB | βhA | βhB | βiAB | βjAB | βjBA | βlAB | |||||
1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 0.5 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |||||
Data | Method | ||||||||||||||||||||
True latent trait | Normal errors | θ | 0.989 | 0.959 | 1.023 | 1.028 | 1.017 | 1.024 | 1.019 | 1.009 | 0.501 | 0.002 | 0.008 | −0.004 | −0.006 | −0.004 | −0.003 | −0.003 | −0.002 | 1.006 | 0.806 |
t | 30.39 | 29.47 | 22.39 | 22.34 | 31.24 | 22.26 | 22.30 | 15.58 | 78.63 | 0.36 | 1.22 | −0.43 | −0.67 | −0.55 | −0.28 | −0.30 | −0.18 | – | – | ||
Normal errors | θ | 1.526 | – | 1.509 | – | – | – | – | – | 0.494 | −0.003 | – | −0.002 | – | – | – | – | – | 1.807 | 0.372 | |
t | 36.91 | – | 25.95 | – | – | – | – | – | 60.97 | −0.40 | – | −0.17 | – | – | – | – | – | – | – | ||
Normal errors | θ | 1.001 | 0.998 | 1.004 | 0.998 | 0.999 | 1.012 | 1.006 | 0.997 | 0.496 | – | – | – | – | – | – | – | – | 1.006 | 0.806 | |
t | 156.6 | 156.3 | 111.7 | 110.6 | 156.5 | 112.1 | 111.9 | 78.4 | 156.3 | – | – | – | – | – | – | – | – | – | – | ||
Logistic regression | θ | 2.964 | 0.428 | 0.538 | 0.627 | 4.287 | 4.487 | 6.934 | 6.840 | 0.623 | 0.332 | −0.189 | −0.206 | 0.201 | 0.102 | 0.070 | 0.605 | 0.611 | – | – | |
t | 0.02 | 0.00 | 0.00 | 0.00 | 0.03 | 0.02 | 0.02 | 0.03 | 0.02 | 0.01 | −0.01 | −0.00 | −0.00 | 0.00 | 0.00 | 0.01 | 0.01 | – | – | ||
Equal item parameters | Sum score | θ | 0.243 | 0.267 | 0.564 | 0.557 | 0.281 | 0.597 | 0.475 | 0.331 | 0.637 | 0.328 | 0.321 | 0.274 | 0.275 | 0.321 | 0.269 | 0.295 | 0.299 | 2.901 | 0.649 |
t | 2.59 | 2.85 | 4.28 | 4.20 | 3.00 | 4.51 | 3.60 | 1.78 | 34.60 | 17.80 | 17.44 | 17.80 | 17.44 | 17.45 | 10.35 | 11.44 | 8.17 | – | – | ||
Square root transformation | θ | 0.400 | 0.400 | 0.476 | 0.452 | 0.425 | 0.480 | 0.456 | 0.430 | 0.214 | 0.032 | 0.031 | 0.018 | 0.023 | 0.028 | 0.019 | 0.024 | 0.025 | 0.685 | 0.736 | |
t | 18.01 | 18.03 | 15.27 | 14.42 | 19.16 | 15.30 | 14.63 | 9.75 | 49.18 | 7.29 | 7.12 | 3.01 | 3.67 | 6.36 | 3.06 | 3.94 | 2.86 | – | – | ||
Variable item parameters | Sum score | θ | 1.860 | 1.911 | 1.847 | 1.946 | 1.977 | 2.001 | 1.908 | 1.934 | 0.900 | 0.015 | 0.003 | 0.017 | −0.007 | −0.014 | −0.017 | 0.008 | −0.002 | 2.418 | 0.725 |
t | 23.75 | 24.11 | 16.81 | 17.59 | 25.25 | 18.15 | 17.37 | 12.43 | 56.68 | 0.99 | 0.18 | 0.81 | −0.33 | −0.93 | −0.77 | 0.37 | −0.06 | – | – | ||
Square root transformation | θ | 0.394 | 0.411 | 0.394 | 0.409 | 0.420 | 0.427 | 0.405 | 0.416 | 0.175 | −0.014 | −0.017 | −0.014 | −0.018 | −0.020 | −0.021 | −0.016 | −0.018 | 0.429 | 0.703 | |
t | 28.33 | 29.57 | 20.20 | 20.83 | 30.23 | 21.74 | 20.76 | 15.06 | 64.45 | −5.13 | −6.40 | −3.74 | −4.66 | −7.44 | −5.40 | −4.18 | −3.38 | – | – |
Estimates from fitting logistic regression to dichotomized sum scores are uninformative and not presented for this model