Exercises: Compute and Interpret the Correlation Coefficient

Work through each section in order. The correlation coefficient r measures the STRENGTH and DIRECTION of a LINEAR association on a scale from -1 to +1. Read its SIGN for direction and its MAGNITUDE (distance from 0) for strength. Where a problem gives a calculator or spreadsheet value, use it as your computed r. Remember: r sees only straight-line patterns, an outlier can swing it, and a high r never proves causation.