Ch 5 · Correlation and Regression

📘 Core concepts

1. 1Correlation measures direction and strength of linear relation (−1 to +1).
2. 2Karl Pearson's coefficient is for quantitative data.
3. 3Spearman's rank correlation for qualitative / ranked data.
4. 4Regression: estimating one variable based on another using best-fit line.
5. 5Two regression lines: Y on X and X on Y; intersect at (x̄, ȳ).