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Learning from Counts: Transition and Emission Tables from a Labelled Logbook, with Add-One Smoothing

Lesson 7 of 815 minLab

This lesson is part of the course

In this lesson

You count weather transitions with COUNTIFS on two shifted ranges, turn them into transition probabilities, estimate emission probabilities from labelled days and use add-one smoothing so that an outcome never seen in a state still gets a small chance.

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Lessons in this course

  1. Markov Chains Refresher: Transition Tables, Rows That Sum to 1 and Two-Step ProbabilitiesLab14 min Locked
  2. Hidden States & Emissions: The Joint Probability of a Weather Path and a LogbookLab16 min Locked
  3. The Forward Algorithm: α Tables Step by Step and the Probability of a LogbookLab16 min Locked
  4. Viterbi Decoding: δ Tables with MAX, Back-Pointers and the Best Path by BacktrackingLab17 min Locked
  5. Log Probabilities: Underflow, LN Sums Instead of Products and Comparing PathsLab14 min Locked
  6. Backward & Smoothing: β Tables and the Posterior Probability of Each Day's WeatherLab17 min Locked
  7. Learning from Counts: Transition and Emission Tables from a Labelled Logbook, with Add-One SmoothingLab15 min Locked
  8. Toy Part-of-Speech Tagging: Three Hidden Tags, Viterbi on a Short Sentence, Accuracy and a Posterior ChartLab18 min Locked