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4MA1/2HR Jan 2019, Question 1: Estimating the Mean for Grouped Data

Pearson Edexcel International GCSE Mathematics A 4MA1 · Paper 2HR (Higher) · Calculator · 5 marks

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The question, in short

From a grouped frequency table for 100 cars and parking duration d, identify the modal class and estimate the mean number of days.

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Part (a) · 1 mark

State which class interval contains the most cars.

  1. 1The modal class is the class with the highest frequency
  2. 2The frequencies are 16, 18, 19, 27, 20
  3. 3The highest frequency is 27
  4. 4This is the class 12 < d ≤ 16
  5. 5The modal class is 12 < d ≤ 16

Answer12 < d ≤ 16

Part (b) · 4 marks

Use class midpoints and frequencies to calculate an estimated mean number of days.

  1. 1Midpoints of the classes: 2, 6, 10, 14, 18
  2. 2Midpoint × frequency: 32, 108, 190, 378, 360
  3. 3Add them: 32 + 108 + 190 + 378 + 360 = 1068
  4. 4Mean = 1068 ÷ 100 = 10.68

Answer10.68

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