Use the table to calculate the average rate of change of f(x) over the interval [0, 4].

The average rate of change over the interval [a, b] is given by
  (f(b) -f(a))/(b -a)

For your interval [0, 4], this is
  (f(4) -f(0))/(4 -0) = (256 -16)/(4 -0) = 240/4 = 60

The average rate of change of f(x) over the interval [0, 4] is 60.