JEE Main 2024 Mathematics question
Consider 10 observations such that and , where α, β are positive integers. Let the mean and the variance of the observations be and respectively. Then is equal to:
Answer: (C)
Solution
Σx = 12, so 12 − 10α = 2 ⇒ α = 1. Σx² = 10(84/25 + 36/25) = 48, so 48 − 24β + 10β² = 40 ⇒ β = 2 (the other root 2/5 is not an integer).