DL26reglin

import matplotlib.pyplot as plt

def prodScal(X,Y):
    n = len(X)
    if n != len(Y) : return
    return sum([X[i]*Y[i] for i in range(n)])/n

def esperance(X):
    return sum(X)/len(X)

def covariance(X,Y):
    return prodScal(X,Y)-esperance(X)*esperance(Y)

def variance(X):
    return sum([x**2 for x in X])/len(X) - esperance(X)**2

def regLin(X,Y):
    n = len(X)
    if n != len(Y) : return
    lbda = covariance(X,Y)/variance(X)
    mu = esperance(Y)-lbda*esperance(X)
    return lbda,mu

def graph(X,Y):
    plt.scatter(X,Y)
    lbda,mu = regLin(X,Y)
    plt.plot(X, [lbda*X[i]+mu for i in range(len(X))])
    plt.show()