The mean and variance of observations are 8 and 16, respectively. If the sum of the first () observations is 48 and the sum of squares of the first () observations is 496, then the value of n is :
- (A)21
- (B)16
- (C)13
- (D)7✓ Correct
Answer: (D)
Solution
Let the -th observation be . The mean gives total , so . The variance gives , i.e. . Substituting ,
Since is a positive integer, .
Since is a positive integer, .
JEE Main · 2026 · 02 Apr 2026 · Shift 2 · Single correct option