What is the interquartile range (IQR) for a test distribution where Q1 = 42 and Q3 = 78?
Answer and explanation
Correct answer: B. 36 marks
- Step 1: Interquartile range IQR = Q3 - Q1. Step 2. Calculation: 78 - 42 = 36 marks. Answer: 36 marks. Why not the others: 30 marks is an arithmetic error; 60 marks is the semi-sum; 120 marks adds Q1 and Q3.
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