The median of a set of 7 distinct observations is 21.5. If each of the largest 3 observations of the set is increased by 4, then the median of the new set -

Correct option is C

Given:

There are 7 distinct observations.

Median of the original set = 21.5

The largest 3 observations are increased by 4.

Concept Used:
For an odd number of observations, the median is the middle (4th) observation after arranging in order.
Since changes are made only to the last 3 (5th, 6th, 7th) elements, the 4th observation (median) remains unchanged.

Solution:
Original median = 4th observation = 21.5
Since the 4th observation is unchanged, the new median is also:

= 21.5 

Median of a new set will remain the same as that of the original set.