Principal Component Analysis Explained 

The best explanation of PCA that I have ever heard, hands down.

It is one of the most intuitive and crystal clear explanation of PCA concept in less than 10 minutes.

Thank you very much, @RayBiotech, for providing this excellent description of PCA!

Thanks! This is amazing!

Thanks for clear explanation

Amazing explanation

Wrong! The maximum number of PC's are min(n-1, k). In the example you had 10 samples and 40 attributes. The answer should be

Good explanation