GCSE · Scatter graphs & correlation

Scatter graphs & correlationExam-style questions

Why one point on a scatter graph is one individual measured twice, how to describe correlation by type and strength in the words of the question, why a correlation never proves a cause, and how to place a line of best fit — through the bulk of the data, balanced either side, ignoring a genuine outlier.

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10 questions · GCSE (Higher) level · mark scheme and worked solution on each · no sign-up to try

DifficultyAll Level 1 Level 2 Level 3 Level 4 Level 5

1
Twelve members of an athletics club each ran $100$ m and each did a long jump. The scatter graph shows each member's $100$ m time, in seconds, and the length of their long jump, in metres.(a) Describe the correlation shown by the scatter graph.

(b) Sam looks at the scatter graph and says: "This proves that a person's sprinting ability affects how far they can long jump."

Explain why the scatter graph does not show this.
Level 3 · 4 marksTry it
2
Ten pupils each sat a maths test and a physics test. Both tests were marked out of $100$ .

Ellie plotted their marks and then joined the points with a ruler, as shown. She says this is her line of best fit.(a) Explain why what Ellie has drawn is not a line of best fit.

(b) Describe the correlation shown by the ten points.
Level 3 · 4 marksTry it
3
Diagram 1 shows, for each of $12$ days, the number of hours of daylight and the number of units of electricity used by a school.Diagram 2 shows, for each of $12$ Year 11 pupils, the time taken to travel to school and the mark scored in a maths test.(a) Describe the correlation shown in Diagram 1.

(b) Describe the correlation shown in Diagram 2.

(c) Explain what your answer to part (b) tells you about travel time and maths marks for these pupils.
Level 3 · 4 marksTry it