I am trying to understand Principal Component Analysis (PCA). I found a webpage on PCA that introduces it and the concept of the percentage of variance. However, I am very confused about what "Percentage of Variance" (POV) means. Here are the questions I have:
- Is there a formal definition or mathematics formula to define "percentage of variance"?
- Do we only use POV for calculating PCA? Is POV used somewhere else?
- Is POV the same as "Proportion of Variance Explained"? (There are many similar terms online which really confuse me.)