Calculus a hard problem

the graph below plots the values of y for different values of x:

plot the ordered pairs 1, 8 and 2, 3 and 3, 0 and 4, 1 and 5, 2 and 6,1

what is the correlation coefficient for the data plotted?

-0.9

-0.6

0.6

0.9

∑x = 1 + 2 + 3 + 4 + 5 + 6 = 21
∑y = 8 + 3 + 0 + 1 + 2 + 1 = 15
∑x^2 = 1 + 4 + 9 + 16 + 25 + 36 = 91
∑y^2 = 64 + 9 + 0 + 1 + 4 + 1 = 79
∑xy = 8 + 6 + 0 + 4 + 10 + 6 = 34

r = (n∑xy - ∑x∑y)/(sqrt(n∑x^2 - (∑x)^2)*sqrt(n∑y^2 - (∑y)^2)) = (6(34) - 21(15))/(sqrt(6(91) - (21)^2)*sqrt(6(79) - (15)^2)) = (204 - 315)/(sqrt(546 - 441)*sqrt(474 - 225)) = -111/(sqrt(105)*sqrt(249)) = -111/(10.25*15.78) = -111/161.7 = -0.68