## 2.7 Cause and Effect

### Correlation and Further Interpretation of the Correlation Coefficient

Note: if you cannot remember how to calculate and interpret the pearson’s correlation coefficient, revise 2.6 Pearson’s Correlation Coefficient.

- Two variables which share a
**statistically meaningful**association are said to be**correlated**. In Further Maths, “statistically meaningful” means they have a pearsons correlation coefficient which indicates an association (r \geq 0.25 or r \leq-0.25). - The strength of a correlation is the same as the strength (weak, moderate or strong) indicated by the pearsons correlation coefficient.
**Correlation does not mean causation**. Keep in mind that correlation is purely statistical and more information is needed to know the nature of the relationship between two variables (this concept is explored further in 2.8 Non-Causal Relationships).