The scatterplot shows the average teacher pay and the per pupil expenditure for each of the 50 states and the District of Columbia. The regression equation is also shown. (Source: The 2017 World Almanac and Book of Facts).
a. From the scatterplot is the correlation between average teacher pay and per pupil expenditure positive, negative, or near zero?
b. What is the slope of the regression equation? Interpret the slope in the context of the problem.
c. What is the $y$ -intercept of the regression equation? Interpret the $y$ -intercept or explain why it would be inappropriate to do so for this problem.
d. Use the regression equation to estimate the per pupil expenditure for a state with an average teacher pay of $$\$ 60,000$$.