The median of a set of 9 distinct observations is 20.5. If each of the largest four observations of the set is increased by 2, then the median of the new set:

Total observations = 9 (odd number)

Median = value at 5th position (middle value) = 20.5

Only the largest 4 observations (i.e., 6th to 9th) are increased by 2

Solution:
Since the median is the middle value (5th term) and we are only changing values after the 5th, the 5th value remains unchanged.

So, the median stays the same.