100% accurate

Hi Erwin,

I have few doubts 

i found you in search of regularization topic 

I have done multiple regression and i observed there is over fitting in my predicted results

My  CEO need 100% accurate predicted model but i don't know how to do regularization for multiple linear regression using excel. Could you please let me know how to do it in a step wise manner or share me any article related to it if you have 

Thank You