The ‘why, what & how’ of PCA (Principal Component Analysis)
Availability of data needs no introduction. And, its needless to say, data drives businesses, these days. For a given business problem, the more features that we capture, the better the analysis. Isn’t it? Or is it?
What if, …
1. There are more dimensions/features than the number of observations?
2. There are too many dimensions, sometimes running into hundreds or more?
The above scenarios define a specific phenomenon called Curse of Dimensionality, which in simple words mean, too many features could actually be a problem. But, how?
Let’s say, we…
Imagine you are on a game show. There are three closed doors in front of you. One door has a car behind it, and the other two doors have a goat. The objective is to try and choose the door that has the car (of course!). You pick a door. Before revealing what’s behind it, the game show host opens one of the two closed doors and shows you a goat. Now, he asks you a question.
“Switch or Stay”?
You have the option to stay with your original choice or switch to the other closed door. …