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WAEC Further Mathematics 2021 Question 39

Question 39

Statistics

The table shows the distribution of marks obtained by some students in a test.
Marks: 0−9, 10−19, 20−29, 30−39, 40−49
Frequency: 4, 12, 16, 6, 2
What is the upper class boundary of the upper quartile class?

  1. A.49.5
  2. B.39.5
  3. C.29.5
  4. D.19.5
Show the answer and explanation

Answer: C (29.5)

Explanation

There are 40 students, so the upper quartile is the 30th mark. Cumulative frequencies 4, 16, 32 put it in 20−29, whose upper boundary is 29.5.