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WAEC Mathematics 1996 Question 47

Question 47

Data Presentation

The marks obtained by pupils of class are grouped as shown below; 0 – 4, 5 – 9, 10 – 14, 15 – 19. Which of the following is/are not true? I. The mid values of the grouped marks are 2, 7, 12 and 17. II The class interval is 4. III The class boundaries are 0.5, 4.5, 9.5, 14.5 and 19.5

  1. A.I only
  2. B.II only
  3. C.III only
  4. D.I and II only
  5. E.II and III only.
Show the answer and explanation

Answer: E (II and III only.)

Explanation

The mid-values 2, 7, 12, 17 are correct. Each class covers 5 marks (e.g. −0.5 to 4.5), so the interval is 5, not 4, and the first boundary is −0.5, not 0.5. So II and III are not true.