Scatter graphs

A scatter graph plots pairs of data to see if they are related. If the points go up together it is positive correlation; if one goes up as the other goes down it is negative; if there is no pattern there is no correlation.

Key facts

  • Positive correlation: points slope upwards.
  • Negative correlation: points slope downwards.
  • A line of best fit goes through the middle of the points, with about as many above as below.
  • Correlation doesn’t prove one thing causes the other.

Worked examples

Example 1

What type of correlation does the graph show?

  1. As you move right, the points go up.
  2. So both increase together: positive correlation.

Answer: Positive