It is believed that exposure to solar radiation increases the pathogenesis of melanoma. Suppose that the following data give sunspot relative number and age-adjusted total incidence (incidence is the number of cases per 100,000 population) for eight different years in a certain region.

(a) Calculate the least-squares regression line for these data.
(b) Plot the points and the least-squares regression line on the same graph.

Sunspot relative number 104 12 40 75110 180 175 30 Incidence total 4.7 1.9 3.8 2.9 0.9 2.7 3.9 16