To find the least squared error in Python, we can use the NumPy package to perform linear regression with the least squares method. The steps to follow are:
Import the NumPy package
Define the independent variable (x) and dependent variable (y) arrays
Use the np.polyfit function to perform a linear regression and find the slope and y-intercept of the line of best fit
Calculate the predicted values of y using the regression equation
Calculate the residuals (the difference between predicted y and actual y values)
Find the sum of the squared residuals
Optimize the sum of squared residuals (or minimize it) using an optimization function like np.optimize.minimize_scalar
Here's an example code block:
main.py
import numpy as np
# Step 1: Define x and y arraysx = np.array([1, 2, 3, 4, 5])
y = np.array([1, 3, 2, 3, 5])
# Step 2: Perform linear regression using np.polyfitslope, intercept = np.polyfit(x, y, 1)
# Step 3: Calculate predicted values of y using the regression equationy_pred = slope * x + intercept
# Step 4: Calculate residualsresiduals = y_pred - y
# Step 5: Find the sum of squared residualssum_sq_err = np.sum(residuals**2)
# Step 6: Optimize sum of squared residuals using np.optimize.minimize_scalardefsum_sq_err_func(slope, x, y): y_pred = slope * x + intercept
residuals = y_pred - y
return np.sum(residuals**2)
opt_result = np.optimize.minimize_scalar(sum_sq_err_func, args=(x, y))
# The optimized slope is:opt_slope = opt_result.x