The median of the following values of a variable 30, 5, 21, 42, 13, 10, 27, 33, 17, 8 is

Arrange the values in ascending order: 5, 8, 10, 13, 17, 21, 27, 30, 33, 42. There are 10 observations, which is even, so the median is the mean of the 5th and 6th values: (17 + 21)/2 = 19. Option A is correct.

Why the others fail:

• B) 17 is the 5th value, only the lower of the two middle terms. Using it ignores the second middle value.
• C) 21 is the 6th value, the upper middle term. It makes the same error in the other direction.
• D) 27 is the 7th value, not a middle position. It comes from miscounting or counting from the wrong end.

Core concept: the median is a positional measure, the middle of ordered data. For an even number of observations it is the average of the two central values. This is basic statistics for the Prelims quantitative and data interpretation section, and it links to central tendency measures used in Mains answers on data-based policy analysis, such as income distribution.

Trap: candidates skip sorting, or after sorting they pick one middle value instead of averaging the two.