The populations an (in millions) of Zimbabwe from 2000 through 2015 are given below as ordered pairs of the form (n, a_n), where n represents the year, with n = 0 corresponding to 2000.

(0, 11.8), (1, 11.9),

(2, 11.9), (3, 11.8),

(4, 11.7), (5, 11.6),

(6, 11.5), (7, 11.4),

(8, 11.4), (9, 11.4),

(10, 11.7), (11, 12.1),

(12, 12.6), (13, 13.2),

(14, 13.8), (15, 14.2)

(a) Use the regression capabilities of a graphing utility to find a model of the form an = bn⁴ + cn³ + dn² + en + f, n = 0, 1, . . . , 15 for the data. Use the graphing utility to plot the points and graph the model.

(b) Use the model to predict the population of Zimbabwe in 2020.