Q.The average deviation from the combined mean of the data series 46, 79, 26, 85, 39, 65, 99, 29, 56, 72 will be — (a) 20.4 (b) 21.4 (c) 19.4 (d) 21
Answer: A
\(n = 10\) And \(\sum{x} = 46 + 79 + 26 + 85 + 39 + 65 + 99 + 29 + 56 + 72 = 596\) \(\therefore\) Mean \((a) = \cfrac{\sum{x}}{n} = \cfrac{596}{10} = 59.6\) We know the deviation of each number from the mean is \(d_i = |x_i - a|\) \(\therefore\) The average deviation will be \(\cfrac{13.6 + 19.4 + 33.6 + 25.4 + 20.6 + 5.4 + 39.4 + 30.6 + 3.6 + 12.4}{10}\) \(= \cfrac{204}{10}\) \(= 20.4\) [Answer]
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