CA Foundation · Quantitative Aptitude · Measures of Central Tendency and Dispersion
The monthly electricity bills (in ₹) of seven households in a Jaipur housing society are 820, 1,150, 640, 980, 1,300, 750 and 900. What is the range and the coefficient of range?
The range is ₹660, the difference between the largest bill 1,300 and the smallest bill 640. The coefficient of range is the range divided by the sum of the extremes, 660/1,940, which equals 0.3402.
- ARange = ₹660; coefficient of range = 0.3402Correct
- BRange = ₹660; coefficient of range = 0.5077
- CRange = ₹1,300; coefficient of range = 0.3402
- DRange = ₹660; coefficient of range = 0.6600
Explanation
Largest = 1,300 and smallest = 640, so range = 1,300 − 640 = 660. Coefficient of range = (L − S)/(L + S) = 660/1,940 = 0.3402. Option B wrongly divides the range by the smallest value (660/1,300 = 0.5077, which actually uses the largest as denominator), not by the sum of the extremes.
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