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4024/22 May/Jun 2021, Question 2: Scatter Diagrams and Correlation

Cambridge O Level Mathematics 4024 · Paper 22 (Calculator) · Calculator · 5 marks

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The question, in short

Using a table of midday temperatures and hot chocolate sales over ten days, plot the remaining data points, describe the correlation, and use a line of best fit to estimate sales at 17 °C.

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

Part (a) · 2 marks

Plot the five remaining data pairs from the table onto the given scatter grid.

  1. 1Plot (21, 8), (6, 17), (5, 21), (12, 16), (23, 6)

AnswerComplete scatter diagram

Part (b) · 1 mark

State the type of correlation shown between temperature and cups sold.

  1. 1As temperature increases, the number of cups of hot chocolate sold decreases (negative correlation)

AnswerAs temperature increases, cups of hot chocolate sold decreases

Part (c) · 2 marks

Draw a line of best fit and use it to estimate cups sold at 17 °C.

  1. 1Draw a ruled line of best fit through the middle of the points, e.g. through the mean point (14.1, 12.6)
  2. 2Read up from 17 °C to the line and across
  3. 3About 10 cups

Answer10 (accept 9 to 11)

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