# Unsupervised Learning

> ML Prep practice set.

- Stable ID: `unsupervised-learning`
- Area: machine-learning
- Timebox: 60 minutes

Optimize and interpret hard clustering and mixture-model assignments.

## Instructions

1. Write the objective or posterior normalization before updating assignments.

## Ordered items

1. [One k-means assignment and update](https://mlprep.iwase.dev/item/original-ml-kmeans/?set=unsupervised-learning) — `original-ml-kmeans` (easy, 7 min)
2. [Mixture responsibilities and EM](https://mlprep.iwase.dev/item/original-ml-gmm/?set=unsupervised-learning) — `original-ml-gmm` (medium, 7 min)
3. [Expectation-maximization for factor analysis](https://mlprep.iwase.dev/item/pml-book1-ex20.1/?set=unsupervised-learning) — `pml-book1-ex20.1` (hard, 30 min)

## Completion

Perform one k-means update and one mixture responsibility calculation.

## Next recommended practice

- [Theory](https://mlprep.iwase.dev/set/theory.md)