The sum of 100 observations and the sum of their squares are 400 & 2475 , respectively. Later on, three observations 3 , 4 & 5 were found to be incorrect. If the incorrect observations are omitted, th

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The sum of 100 observations and the sum of their squares are 400 & 2475 , respectively. Later on, three observations 3 , 4 & 5 were found to be incorrect. If the incorrect observations are omitted, then the variance of the remaining observations is

TestHub · Accepted Answer

Given ∑ i = 1 10 x i = 400 and ∑ i = 1 100 x i 2 = 2475 Variance of 97 observations = σ 2 = ∑ x i 2 N - ∑ x i N 2 ∴ 3 + 4 + 5 = 12 , 3 2 + 4 2 + 5 2 = 50 = 2425 97 - 388 97 2 = 2425 97 - 16 = 2425 - 1552 97 = 873 97 = 9

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