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Auralith Learning

Year 8 · Maths · Representing data · Lesson 2

Scatter graphs and correlation

Learn to plot scatter graphs, describe positive, negative and no correlation, spot outliers, predict correlations in real life, and understand that correlation doesn't prove cause.

Whiteboard video lesson: Scatter graphs and correlation

24-minute video lesson

Teaching, worked examples and 20 practice questions solved step by step.

Watch free for a month

What your child will learn

  • Plot data on a scatter graph
  • Describe positive, negative and no correlation
  • Explain what a correlation means in context
  • Identify outliers
  • Understand that correlation does not prove cause

The method

  1. Look at the points from left to right.
  2. Going up: positive correlation. Going down: negative correlation.
  3. No pattern: no correlation.
  4. Explain what it means using the axis labels.

Key words: scatter graph, correlation, positive, negative, outlier.

Worked examples

The first three practice questions from the lesson, with every step.

Question 1

Describe the correlation shown by the scatter graph.

  1. Step 1: Look at the pattern of the points
  2. Step 2: As hours revised goes up, the test score goes up.
  3. Step 3: More revision: higher scores

Answer: Positive correlation

Question 2

Describe the correlation shown by the scatter graph.

  1. Step 1: Look at the pattern of the points
  2. Step 2: As temperature goes up, ice cream sales goes up.
  3. Step 3: Hotter days: more ice creams sold

Answer: Positive correlation

Question 3

Describe the correlation shown by the scatter graph.

  1. Step 1: Look at the pattern of the points
  2. Step 2: As hours of TV goes up, hours of sleep goes down.
  3. Step 3: More TV: less sleep

Answer: Negative correlation