UPSC CDS 1 2021 Math Paper

Concept:The median is the middle value when data is arranged in ascending order.Explanation:Step 1: Arrange the given data in ascending order.The data is $2, 3, -1, 2, 6, 8, 9$.Sorted order: $-1, 2, 2, 3, 6, 8, 9$.Step 2: Count the number of observations.There are $n = 7$ observations, which is odd.Step 3: For an odd number of observations, the median is the $\left(\frac{n+1}{2}\right)^{\text{th}}$ term.Here, $\frac{7+1}{2} = 4$, so the median is the 4th term.Step 4: The 4th term in the sorted list is $3$.Therefore, the median is $3$.Answer:$3$ (Option B).