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0580/11 May/Jun 2025, Question 20: Scatter Diagrams and Correlation

Cambridge IGCSE Mathematics 0580 · Paper 11 (Core) · Non-calculator · 4 marks

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The question, in short

Scatter diagram of petrol price per litre against litres sold over ten days; add two more data points, identify correlation, draw a line of best fit and use it to estimate litres sold at $1.55 per litre.

Summarised in our own words. Use the official paper for the exact wording and the diagram.

Part (a) · 1 mark

Plot the two extra days' data, price $1.68 with 90 litres and $1.47 with 380 litres, on the scatter diagram.

  1. 1Plot a cross at (1.68, 90) and a cross at (1.47, 380)

Answer2 points accurately plotted

Part (b) · 1 mark

State the type of correlation shown by the scatter diagram.

  1. 1As price increases, litres sold decreases: negative correlation

AnswerNegative

Part (ci) · 1 mark

Draw a line of best fit on the scatter diagram.

  1. 1Rule one straight line through the middle of the points, sloping down
  2. 2Roughly as many points above the line as below, e.g. from (1.45, 415) to (1.65, 135)

AnswerCorrect ruled line of best fit

Part (cii) · 1 mark

Using your line of best fit, estimate the number of litres sold when the price is $1.55 per litre.

  1. 1Go up from 1.55 to the line and across to the vertical axis
  2. 2≈ 275 litres

Answer275

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Also searched as: 0580/11/M/J/25 · 0580_s25_qp_11 · 0580 s25 11 · question 20.
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