Challenge

Supervised Learning - Prediction Week 3 Challenge

1. Gradient Descent with any Loss Function:

  • Gradient Descent is an iterative optimization algorithm used to minimize a loss function.

import numpy as np

def gradient_descent(X, y, learning_rate, epochs):

m, b = 0, 0 # Initial guess

n = len(X)

for epoch in range(epochs):

y_pred = m * X + b

loss = np.mean((y_pred - y)**2)

gradient_m = 2/n * np.sum(X * (y_pred - y))

gradient_b = 2/n * np.sum(y_pred - y)

m -= learning_rate * gradient_m

b -= learning_rate * gradient_b

print(f'Epoch {epoch+1}/{epochs}, Loss: {loss:.4f}')

return m, b

2. Difference between L1 & L2 Gradient Descent:

  • L1 and L2 refer to regularization terms added to the loss function to prevent overfitting.
  • L1 regularization (Lasso): Adds the absolute values of the coefficients. Encourages sparsity.
  • L2 regularization (Ridge): Adds the squared values of the coefficients. Tends to shrink coefficients.

3. Loss Functions for Regression:

  • Mean Squared Error (MSE)
  • Mean Absolute Error (MAE)
  • Huber Loss
  • Quantile Loss
  • Log-Cosh Loss

4. Importance of Learning Rate:

  • The learning rate controls the size of the steps taken during optimization.
  • Too high a learning rate may cause overshooting, and too low a learning rate may result in slow convergence or getting stuck in local minima.
  • It's crucial to choose an appropriate learning rate for efficient and stable convergence.

5. Evaluation of Linear Regression:

  • Mean Squared Error (MSE)
  • Mean Absolute Error (MAE)
  • R-squared (Coefficient of Determination)
  • Adjusted R-squared
  • Residual Analysis (checking residuals for normality, homoscedasticity)

6. Difference between Multiple and Adjusted Coefficient of Determination:

  • Multiple Coefficient of Determination (R-squared) measures the proportion of the variance in the dependent variable that is predictable from the independent variables.
  • Adjusted R-squared adjusts R-squared for the number of predictors in the model, penalizing for adding irrelevant predictors. It provides a more accurate measure when comparing models with different numbers of predictors.
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