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NTA Abhyas JEE Main2020MathematicsStatisticsPractice

Let x 1 , x 2 , … x n be n observations such that ∑ x i 2 = 500 and ∑ x i = 100 . Then, an impossible value of n among the following is

Options

  1. A24
  2. B18
  3. C29
  4. D22

Correct answer

B. 18

Step-by-step solution

Variance = ∑ x i 2 n - ∑ x i n 2 ≥ 0 ⇒ ∑ x i 2 n ≥ ∑ x i 2 n 2 ⇒ n ≥ ∑ x i 2 ∑ x i 2 ⇒ n ≥ 10000 500 ⇒ n ≥ 20

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