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A frequency distribution has the following class intervals and frequencies: 0-6 (frequency 4), 6-12 (frequency 5), 12-18 (frequency 3), 18-24 (frequency 6), 24-30 (frequency 2). What is the mean deviation from the median of this data?
- 7
- 7.5
- 6
- 6.5
Correct answer: 7
Solution
Median = 12 + (10 - 9)/3 * 6 = 14. Using midpoints 3, 9, 15, 21, 27 and their deviations from 14: mean deviation = (4*11 + 5*5 + 3*1 + 6*7 + 2*13)/20 = 140/20 = 7.
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