total = sum(data) ave = float(total)/lenth tempsum = sum([pow(data[i] - ave,2) for i in range(lenth)]) tempsum = pow(float(tempsum)/lenth,0.5) for i in range(lenth): data[i] = (data[i] - ave)/tempsum return data print Z_Score([2,2,3,4,5,6,7,8]) print Z_Score([10,20,30,40,50,60,70,80]) print Z_Score([20,20,30,40,50,60,70,80])