A simple python program to calculate co variance and correlation of two variables

statistics.py

a = [25,35,21,67,98,27,64] # data points
b = [52,10,5,98,52,36,69] # data points

from statistics import mean

meanA = mean(a)
meanB = mean(b)

# find co variance
coVariance = 0

for i in range(0, len(a)):
	coVariance += (((a[i]-meanA)*(b[i]-meanB)) / (len(a) - 1) )

print("Co variance is",coVariance)

import math

varianceA = 0.0
varianceB = 0.0

for x in a:
	c = (x - meanA) ** 2
	varianceA += c

varianceA = varianceA / (len(a)-1)

for y in b:
	d = (y - meanB) ** 2
	varianceB += d

varianceB = varianceB / (len(b)-1)

# calculate standard deviation
stdA = math.sqrt(varianceA)
stdB = math.sqrt(varianceB)

# calculating correlation
correlation = coVariance / (stdA * stdB)
print("Correlation is "+ str(correlation))