Lemmara logoLemmaraWorked solution

4024/12 Oct/Nov 2021, Question 21: Finding the Median and Quartiles

Cambridge O Level Mathematics 4024 · Paper 12 (Non-calculator) · Non-calculator · 5 marks

اقرأ هذا الحل مشروحاً بالعربي ←

The question, in short

From a cumulative frequency graph of the masses of 120 eggs, estimate the median and interquartile range, and find how many eggs are 63 g or more.

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

Part (ai) · 1 mark

Use the cumulative frequency diagram to estimate the median mass of the 120 eggs.

  1. 1Median at cumulative frequency 120 ÷ 2 = 60
  2. 2Reading across from 60: median = 58 g

Answer58

Part (aii) · 2 marks

Use the diagram to estimate the interquartile range of the egg masses.

  1. 1Lower quartile at 120 ÷ 4 = 30: 51 g
  2. 2Upper quartile at 3 × 120 ÷ 4 = 90: 62 g
  3. 3IQR = 62 − 51 = 11 g

Answer11

Part (b) · 2 marks

Given that eggs of mass 63 g or more are large, find how many of these eggs are large.

  1. 1Read up from m = 63 to the curve, then across: about 98 (96 to 99)
  2. 2So about 98 eggs weigh less than 63 g
  3. 3Large eggs = 120 − 98 = 22, so 21 to 24

Answer21 to 24

Stuck on a step? Read the free lesson: Finding the Median and Quartiles

Practise more finding the median and quartiles questions

Real 4024 past-paper questions, marked on your working like the exam, with a worked solution for every part.

Practise free on Lemmara

More past-paper questions on finding the median and quartiles

Also searched as: 4024/12/O/N/21 · 4024_w21_qp_12 · 4024 w21 12 · question 21.
Lemmara is an independent study tool, not affiliated with or endorsed by Cambridge International Education. The worked solutions are Lemmara’s own.