JEE Main 2024 Mathematics question
Let a, b ∈ R. Let the mean and the variance of 6 observations −3, 4, 7, −6, a, b be 2 and 23, respectively. The mean deviation about the mean of these 6 observations is:
Answer: (A)
Solution
a + b = 10 and a² + b² = 52, so {a, b} = {4, 6}. Mean deviation about 2 = (5 + 2 + 5 + 8 + 2 + 4)/6 = 13/3.