1. Logistic Regression (Classification Algorithm)

2. Classification Problem
Spam/Not Spam?
Online Transactions: Fraudulent (Yes/No)?
Tumor: Malignant/Benign

3. Classification Problem
Spam/Not Spam?
Online Transactions: Fraudulent (Yes/No)?
Tumor: Malignant/Benign
Prediction Task:

4. Classification Problem
Spam/Not Spam?
Online Transactions: Fraudulent (Yes/No)?
Tumor: Malignant/Benign
Prediction Task:
This is an example of Binary Classification task. A generalized case of classification task in Multi-class Classification

5. Applying Linear Regression

6. Applying Linear Regression
hθ(x)

7. Applying Linear Regression
hθ(x)

8. Problem in Applying Linear Regression
Yes(1)
No(0)
Tumor Size

9. Problem in Applying Linear Regression
Yes(1)
No(0)
Tumor Size

10. Problem in Applying Linear Regression
Yes(1)
No(0)
Tumor Size

11. Problem in Applying Linear Regression
Yes(1)
No(0)
Tumor Size
Benign if tumor size lies in this range
Malignantif tumor size lies in this range

12. Problem in Applying Linear Regression

13. Hypothesis Representation
hθ(x) = θTx

14. Hypothesis Representation
g(z)
Sigmoid function
Logistic function z

15. Interpretation of Hypothesis Output
hθ(x) = P(y=1|x;θ)

16. Interpretation of Hypothesis Output

17. Interpretation of Hypothesis Output
g(z) z

18. Decision Boundary

19. Decision Boundary

20. Decision Boundary

21. Decision Boundary

22. Decision Boundary

23. Decision Boundary

24. Learning Task

25. Cost Function

26. Cost Function

27. Logistic Regression Cost Function

28. Logistic Regression Cost Function

29. Logistic Regression Cost Function

30. Logistic Regression Cost Function

31. Logistic Regression Cost Function

32. Logistic Regression Cost Function

33. Logistic Regression Cost Function

34. Logistic Regression Cost Function

35. Gradient Descent

36. Gradient Descent

37. Gradient Descent
Algorithm looks identical to linear regression

38. Multi-class Classification: One-vs-All Algorithm

39. Binary vs Multi-class Classification Problem

40. One-vs-All (one-vs-rest)

41. One-vs-All (one-vs-rest)

42. One-vs-All (one-vs-rest)

43. One-vs-All (one-vs-rest)

44. One-vs-All Algorithm