The mean and variance of five observations are 14 and 13 2 respectively. Three of the five observations are 11, 16 and 20. What are the other two observations?

NDA 2023 Mathematics question

The mean and variance of five observations are 14 and respectively. Three of the five observations are 11, 16 and 20. What are the other two observations?

(A)8 and 15
(B)9 and 14
(C)10 and 13Correct
(D)11 and 12

Answer: (C)

Solution

Let the other two be and . Sum: . Sum of squares: $ = 5(13·2+ =

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Question ID VK-029632