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importnumpyasnp
importmatplotlib.pyplotasplt
defestimate_coef(x, y):
# number of observations/points
n=np.size(x)
# mean of x and y vector
m_x, m_y=np.mean(x), np.mean(y)
# calculating cross-deviation and deviation about x
SS_xy=np.sum(y*x) -n*m_y*m_x
SS_xx=np.sum(x*x) -n*m_x*m_x
# calculating regression coefficients
b_1=SS_xy/SS_xx
b_0=m_y-b_1*m_x
return(b_0, b_1)
defplot_regression_line(x, y, b):
# plotting the actual points as scatter plot
plt.scatter(x, y, color="m", marker="o", s=30)
# predicted response vector
y_pred=b[0] +b[1]*x
print("pred value of ", y," is ", y_pred)
print("error at ",y," is," ,y-y_pred)
# plotting the regression line
plt.plot(x, y_pred, color="g")
# putting labels
plt.xlabel('x')
plt.ylabel('y')
# function to show plot
plt.show()
defmain():
# observations
x=np.array([5,7,10,15,23])
y=np.array([10,20,30,40,50])
# estimating coefficients
b=estimate_coef(x, y)
print("Estimated coefficients:\nb_0 = {} \nb_1 = {}".format(b[0], b[1]))
# plotting regression line
plot_regression_line(x, y, b)
if__name__=="__main__":
main()