A linear mathematical model for predicting prize winnings at a race is based on data for 3 years. Create an example of such a model and then write a paragraph discussing the potential accuracy or inaccuracy of it.

The distribution of the amount of money spent by students for textbooks in a semester is approximately normal in shape with a mean of $235 and a standard deviation of $20. according to the standard deviation rule, how much did almost all (99.7%) of the students spend on textbooks in a semester?