Nell Dursley attended a public lecture by a famous investment analyst. In the lecture, the analyst demonstrated his new model for estimating returns on a portfolio. The model intrigued Nell and after returning home, he recreated the model from memory and verified it using past data. Highly confident that the model will work wonders, Nell emailed all his clients that he has discovered a new model and explained in some detail the working of the model. Which of the following is most accurate?