Question

The mean deviation from the median of the following set of observations 5, 3, 9, 12, 3, 10, 12, 21, 18, 12, 21 is

• A. 5.113
• B. 4.606
• C. 4.134
• D. 4.909

Answer 1

Answer: (D)

4.909

Answer 2

There are 11 observations, on arranging these observations in ascending order of magnitude, we get 3, 3, 5, 9, 10, 12, 12, 12, 18, 21, 21 The number of observations n ( = 11) is an odd number, therfore, median $M = \frac{11 +1}{2}$ the observation = 6th observation = 12 For the mean deviation (about median), construct the following table : $\therefore$ Mean deviation (about median) $= \frac{\sum |x_i - M |}{n} = \frac{\sum |x_i - 12|}{n} = \frac{54}{11} = 4.909$