Dear Victor,
hank you so much for your answer! I found it very useful.
I followed your instructions and obtained the results I was aiming for. What I realized is that the significant parameter interactions need to be selected in the "Fit Model" based on those shown in the "Fit Definitive Screening". Otherwise, all parameter interactions will be considered, which can lead to different results for the p-values and R-squared (Rsp) of the model.
Another question that comes to mind relates to my experiments, where I converted biomass into biochar. The solid yield and heating value of the biochar are well predicted by the model. However, there is one indirect response (e.g., ash composition of biochar), which is analyzed by combusting the biochar at 550°C to determine the ash composition. This indirect response shows a very high RMSE (Root Mean Square Error) of 2930 in the model.
How should I interpret this high RMSE? Can I conclude that this model is not suitable for predicting this indirect response?
Best regards