Scatter graphs and correlation
Plot pairs of data; describe correlation as positive, negative or none. Year 8-9.
Scatter graphs show two variables per data point. Trends: positive (both increase together), negative (one up, one down), no correlation (random scatter). A line of best fit (drawn by eye) lets you predict.
Worked examples
Height vs shoe size: positive correlation.
Age vs price of used cars: typically negative correlation.
Birthday vs maths score: no correlation.
Frequently asked questions
Strong vs weak correlation?
Strong: points cluster tightly around a straight line. Weak: scattered but a trend visible. None: no pattern.
Is correlation causation?
No — two variables can correlate without one causing the other. KS4 introduces causation vs correlation language.