import numpy as np
import math
def computeCorrelation(x,y):
xBar=np.mean(x)
yBar=np.mean(y)
SSR,varX,varY=0,0,0
for i in range(len(x)):
diffXBar=x[i]-xBar
diffYBar=y[i]-yBar
SSR+=diffXBar*diffYBar
varX+=diffXBar**2
varY+=diffYBar**2
SST=math.sqrt(varX*varY)
return SSR/SST
testX=[1,3,4,6,9]
testY=[15,18,20,26,30]
print computeCorrelation(testX, testY)