Analyze Variability
Coefficients Table - Coefficients
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Analyze VariabilityCoefficients Table - Coefficients |
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Each term in the model has a coefficient. Use the coefficients to construct an equation representing the relationship between the response and the factors.
To use this equation, use Stat > DOE > Factorial > Predict to calculate the predictions and confidence intervals for predictor values that you specify.
Example Output |
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Coded Coefficients for Ln(Std)
Ratio Term Effect Effect Coef SE Coef T-Value P-Value VIF Constant 0.3424 0.0481 7.12 0.001 Material -0.9598 0.3830 -0.4799 0.0481 -9.99 0.000 1.00 InjPress -0.1845 0.8315 -0.0922 0.0481 -1.92 0.113 1.00 InjTemp 0.0555 1.0571 0.0278 0.0481 0.58 0.589 1.00 CoolTemp -0.1259 0.8817 -0.0629 0.0481 -1.31 0.247 1.00 Material*InjPress -0.9918 0.3709 -0.4959 0.0481 -10.32 0.000 1.00 Material*InjTemp 0.1875 1.2062 0.0937 0.0481 1.95 0.109 1.00 Material*CoolTemp 0.0056 1.0056 0.0028 0.0481 0.06 0.956 1.00 InjPress*InjTemp -0.0792 0.9239 -0.0396 0.0481 -0.82 0.448 1.00 InjPress*CoolTemp -0.0900 0.9139 -0.0450 0.0481 -0.94 0.392 1.00 InjTemp*CoolTemp 0.0066 1.0066 0.0033 0.0481 0.07 0.948 1.00 |
Interpretation |
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For the insulation data, the regression equation is:
Natural log of standard deviation (Strength) = 0.3424 - 0.4799(Material) - 0.0922(InjPress) + 0.0278(InjTemp) - 0.0629(CoolTemp) - 0.4959(Material*InjPress) + 0.0937(Material*InjTemp) + 0.0028(Material*CoolTemp) - 0.0396(InjPress*InjTemp) - 0.0450(InjPress*CoolTemp) + 0.0033(InjTemp*CoolTem)
You may want to refit the model excluding the nonsignificant terms.
