Table 2 Illustration of the models used to estimate the residuals for each of the growth pattern contrasts for the birth to 6 week period. The outcome can then be regressed onto the residuals in a second analytical modela
Model | Model to estimate residual for the birth to 6 week periodb |
|---|---|
(a) Conditional growth: | z 1.5, i = λ 0 + λ 1 z 0,i + ε i |
(b) Being bigger: | z 0, i = η 0 + η 1(z 1.5,i − z 0,i ) + ε i |
(c) Becoming bigger and staying bigger: | (z 1.5, i − z 0, i ) = λ 0 + λ 1 z 0 + λ 2(z 3 − z 1.5) + λ 3(z 6 − z 3) + λ 4(z 12 − z 6) + λ 5(z 24 − z 12) + ε i |
(d) Growing faster versus being bigger: | (z 1.5, i − z 0, i ) = λ 0 + λ 1 z 1.5 + ε i |
(e) Becoming bigger versus being bigger: | (z 1.5, i − z 0, i ) = λ 0 + λ 1(z 3 − z 1.5) + λ 2(z 6 − z 3) + λ 3(z 12 − z 6) + λ 4(z 24 − z 12) + λ 5 z 24 + ε i |