dagov 2872 obtaining a linear model from data use two points on best attempt at sketched line appr

To estimate the equation of a best-fit straight line, sketch a plot of data points and the straight line that comes as close as possible, on the average, to the data points (technically you want to minimize the average of the squares of the vertical distances of the data points from the line). Then pick two points on the line, not close together (and not data points) and plug the coordinates of each into on of the forms of a linear function. Solve the simultaneous equation for the parameters of that form and substitute them into the form to obtain your function.