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4024/11 May/Jun 2021, Question 11: Relative Frequency and Expectation

Cambridge O Level Mathematics 4024 · Paper 11 (Non-calculator) · Non-calculator · 4 marks

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The question, in short

Use a survey probability about women's heights and a relative frequency table for housing plans A, B, C to find a probability, a count for plan A, and the total surveyed.

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

Part (a) · 1 mark

Given 3 in 100 women exceed 1.9 m, find the probability a randomly chosen woman is not taller than 1.9 m.

  1. 1P(not taller) = 1 − 3/100 = 97/100 = 0.97

Answer0.97 or 97/100

Part (bi) · 2 marks

Using relative frequencies 0.3, 0.5, 0.2 and 52 people choosing C, find how many chose A.

  1. 1Total = 52 ÷ 0.2 = 260
  2. 2Plan A = 0.3 × 260 = 78

Answer78

Part (bii) · 1 mark

Using the relative frequency for plan C and its count of 52, calculate the total number of people surveyed.

  1. 1Total = 52 ÷ 0.2 = 260

Answer260

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Also searched as: 4024/11/M/J/21 · 4024_s21_qp_11 · 4024 s21 11 · question 11.
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