The final model in the Linthurst example in this chapter used pH and Na content of the marsh substrate as the independent variables for predicting biomass (in the forward selection and stepwise...

The final model in the Linthurst example in this chapter used pH and Na content of the marsh substrate as the independent variables for predicting biomass (in the forward selection and stepwise methods). The regression equation was

What inference are you willing to make about the relative importance of pH and Na versus SALINITY, K, and Z_n
as biologically important variables in determining biomass? When all five variables were in the model, the partial regression coefficient for pH was a no nsignificant −.009(±.016). Does this result modify your inference?