Asked about Finding structure without labels
What is PCA doing?
An answer that works
Finding the orthogonal directions of greatest variance and projecting the data onto the first few. It compresses while keeping as much variance as possible, and the components are interpretable as weighted combinations of the original features.
Reading an answer is not being able to give one. The section that teaches this is Finding structure without labels, 5 hours of Unsupervised learning.
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