Find the mean deviation about the MEDIAN for the data 5, 7, 9, 11, 38.

The values are already in order, so the median is the 3rd one, 9. The absolute deviations from 9 are 4, 2, 0, 2 and 29, which add to 37, so the mean deviation about the median is 37 ÷ 5 = 7.4. The option 9.6 is the mean deviation about the MEAN: the mean is 70 ÷ 5 = 14 and the deviations 9, 7, 5, 3, 24 add to 48. Deviations measured from the median always give the smaller total, which is why the median is the better centre for lopsided data like this. The option 9 is the median itself.