0580/31 May/Jun 2026, Question 16: Scatter Diagrams and Correlation
Cambridge IGCSE Mathematics 0580 · Paper 31 (Core) · Calculator · 4 marks
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The question, in short
Scatter graph links daily hot drink sales to average temperature; add two extra data pairs, identify correlation, fit a line, and use it to estimate sales at 24 °C.
Summarised in our own words. Use the official paper for the exact wording and the diagram.
Part (a) · 1 mark
Mark the two given temperature and hot drinks pairs as points on the scatter graph.
- 1Plot a cross at temperature 18, drinks 40
- 2Plot a cross at temperature 28, drinks 21
Answer(18, 40) and (28, 21) plotted
Part (b) · 1 mark
State which kind of correlation the plotted points indicate.
- 1As temperature increases, the number of hot drinks sold decreases
- 2Negative correlation
AnswerNegative
Part (ci) · 1 mark
Add a straight line of best fit to the scatter graph.
- 1Draw a single ruled line through the middle of the points, sloping down
- 2It should pass near (16, 42), (24, 29) and (32, 15)
AnswerRuled line of best fit passing through (16, 39) to (16, 46), (24, 27) to (24, 31) and (32, 11) to (32, 18)
Part (cii) · 1 mark
Using your fitted line, estimate hot drinks sold when the average temperature is 24 °C.
- 1Go up from 24 °C to the line of best fit, then across to the vertical axis
- 2About 29 hot drinks
Answer28 (accept 26 to 31)
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Also searched as: 0580/31/M/J/26 · 0580_s26_qp_31 · 0580 s26 31 · question 16.
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