I have research on competition between rice and Commelina diffusa. I have the data on yield and components of rice as well as the growth parameters of the weed. My concerns are that I don't understand much about the parameters of the model like how to do "i" which is the % yield loss per weed plant per unit as weed density approaches zero and a as approaches infinity. Also, how to compute the equation in the excel? Thanks for any help you can extend to my questions.

Dindo