The Dallas Cowboys want to know how many more people they are expecting to come to their future games. Their building is already maxed out, but they need to know about the growth of ticket sales to decide whether to build a larger stadium. What would be the independent variable (Y) and what would be the dependent variable (X) in this example? Would the slope of the line be positive or negative? Also, once you create a line, how would you use the slope of the line in Y = B0 + B1X + E as a forecasting tool to solve the owners' problem?