Table 8 Parameter estimates and their standard errors and tests of significance for the model Eq. (5) to predict the longitudinal variation in wood density
From: Modelling the variation in wood density of New Zealand-grown Douglas-fir
Parameter | Estimate | Std. error | t Value | p Value |
|---|---|---|---|---|
a | 436.6 | 6.0 | 73.2 | <0.0001 |
b | −126.4 | 15.2 | −8.30 | <0.0001 |
c | 243.7 | 44.0 | 5.54 | <0.0001 |
d | −167.5 | 34.1 | −4.92 | <0.0001 |
\( {\sigma}_{s \tan d}^2 \) | 538.0 | 215.5 | 2.50 | 0.0063 |
\( {\sigma}_{tree\left(s \tan d\right)}^2 \) | 640.0 | 79.3 | 8.07 | <0.0001 |
\( {\sigma}_e^2 \) | 355.1 | 16.0 | 22.23 | <0.0001 |