simple_lr.py

import csv
dot = lambda a,b: sum(i*j for i,j in zip(a,b))
mean = lambda a: sum(a)/len(a)
rows = list(csv.DictReader(open("insurance.csv")))
data= {k: [float(i[k]) for i in rows] for k in rows[0]}
x, y = data['X'], data['Y']
n = len(x)
beta1 = (n*dot(x,y)-sum(x)*sum(y))/(n*dot(x,x)-sum(x)**2)
beta0 = mean(y)-beta1*mean(x)
print("beta0 = ",beta0,",beta1 = ",beta1)
# result:
# beta0 =  19.994485759114784 ,beta1 =  3.413823560066368