Table 5 Results of the response surface quadratic (nonlinear) model for the throughfall rate in the P. tabulaeformis forest in the study area.
From: Factors controlling throughfall in a Pinus tabulaeformis forest in North China
Regression | DF | Type I Sum of Squares | R-Square | F Value | Pr > F |
|---|---|---|---|---|---|
Linear | 2 | 13860.00 | 0.74 | 90.72 | <0.0001 |
Quadratic | 2 | 1927.10 | 0.10 | 12.61 | <0.0001 |
Cross Product | 1 | 37.87 | 0.0020 | 0.50 | 0.49 |
Total Model | 5 | 15825.00 | 0.85 | 41.43 | <0.0001 |
Residual | DF | Sum of Squares | Mean Square | ||
Total Error | 37.00 | 2826.44 | 76.39 | ||
Factor | DF | Sum of Squares | Mean Square | F Value | Pr > F |
X 6 | 3.00 | 10258.00 | 3419.47 | 44.76 | <0.0001 |
X 7 | 3.00 | 5147.46 | 1715.82 | 22.46 | <0.0001 |
Parameter | DF | Estimate | Standard Error | T Value | Pr > |t| |
Intercept | 1 | 230.58 | 55.01 | 4.19 | 0.0002 |
X 6 | 1 | −436.87 | 127.01 | −3.44 | 0.0015 |
X 7 | 1 | 51.43 | 15.76 | 3.26 | 0.0024 |
X 6 × X 6 | 1 | 192.18 | 76.35 | 2.52 | 0.016 |
X 7 × X 6 | 1 | 8.73 | 12.41 | 0.70 | 0.49 |
X 7 × X 7 | 1 | −11.87 | 2.81 | −4.23 | 0.0001 |
