Logistic regression and probabilities

Linear Classifiers in Python

Michael (Mike) Gelbart

Instructor, The University of British Columbia

Logistic regression probabilities

Without regularization $(C=10^8)$:

  • model coefficients: [[1.55 1.57]]
  • model intercept: [-0.64]
Linear Classifiers in Python

Logistic regression probabilities

Without regularization $(C=10^8)$:

  • model coefficients: [[1.55 1.57]]
  • model intercept: [-0.64]
Linear Classifiers in Python

Logistic regression probabilities

Without regularization $(C=10^8)$:

  • model coefficients: [[1.55 1.57]]
  • model intercept: [-0.64]

With regularization $(C=1)$:

  • model coefficients: [[0.45 0.64]]
  • model intercept: [-0.26]
Linear Classifiers in Python

How are these probabilities computed?

  • logistic regression predictions: sign of raw model output
  • logistic regression probabilities: "squashed" raw model output

Linear Classifiers in Python

Let's practice!

Linear Classifiers in Python

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