Simpson's Rule calculation for the integral, A_n, where h is the sampling interval, is given by the recurrence relation: A_n=A_n-2+h(y_n-2+4y_n-1+y_n)/3 for n>2 with A₀=0. For an even number of points, Simpson's 4/3 rule is used for the final three slices i.e. A_n=A_n-3+3h/8(y_n-3+3y_n-2+3y_n-1 +y_n)