Lessons for Topic 5.2
Correlation is not causation: lurking and confounding variablesWhen two possible causes change together so their effects cannot be told apart.Lesson
The correlation coefficientA number between negative one and one measuring how closely points cluster about a straight line.Lesson
Properties of the correlation coefficientIt has no units, does not change if the variables are swapped, and never leaves the interval from negative one to one.Lesson
Correlation from standardized valuesFinding r as the average product of the two variables' z-scores.Lesson