If I have five variables, each with four sub-questions, In each sub-question, I have: 1 = I usually don't do this at all 2 = I usually do this a little bit 3 = I usually do this a medium amount 4 = I usually do this a lot
If the values of my five variables are the sum of their sub-questions' scores, do I need to standardize them if I want to use PCA? Do you recommend using correlation or covariance matrix to construct PCs?
