correlation

Everyday

1. A connection or relationship between two things, where they change together. tree →
2. (maths, science) A measure of how closely two sets of numbers go up or down together, as shown on a scatter graph. tree →

In the lessons

In maths and science lessons pupils draw scatter graphs and describe positive correlation (both go up), negative correlation (one goes up, the other down) or no correlation. A key idea: correlation does not prove causation. Phrases: "positive correlation", "negative correlation", "no correlation", "a strong correlation".

Examples

• There is a positive correlation between height and shoe size. tree →
• The graph shows a negative correlation: as temperature rises, coat sales fall. tree →
• There was no correlation between hair colour and test scores. tree →
• Correlation does not mean one thing causes the other. tree →
• Scientists found a correlation between exercise and sleep. tree →

Note

Spelling: double r. In maths, positive correlation = points slope upward; negative = points slope downward; no correlation = points scattered. A correlation alone does not prove one thing causes the other.