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The mean of 40 observations is 20 and their standard deviation is 5 . If the sum of the squares of the observations is k , then the value of k 1000 is

Correct answer

17

Step-by-step solution

n = 4 0 x ¯ = 2 0 σ = 0 5 σ 2 = ∑ x i 2 40 - x ¯ 2 25 = ∑ x i 2 40 - 400 ⇒ ∑ x i 2 = 1700 0

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