A random sample of 4 professional athletes produced the following data where x is the number of endorsements the player has and y is the amount of money made (in millions of dollars).
a. Find an equation of the least squares regression line. Show all work; writing the correct equation, without supporting work, will receive no credit.
b. Based on the equation from part (a), what is the predicted value of y if x = 4? Show all work and justify your answer.