The upper quartile of a class test is 74 and the lower quartile is 54. What is the semi-interquartile range?
Answer and explanation
Correct answer: B. 10 marks
- Step 1: Semi-interquartile range = (Q3 - Q1) / 2. Step 2. Calculate: (74 - 54) / 2 = 20 / 2 = 10 marks. Answer: 10 marks. Why not the others: 14 marks is an arithmetic error; 20 marks is the full interquartile range; 24 marks subtracts incorrectly.
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