NTA Abhyas JEE Main2020MathematicsStatisticsPractice

The variance of the first 20 positive integral multiples of 4 is equal to

Options

A532
B133
C266
D600

Correct answer

A. 532

Step-by-step solution

The numbers are 4 , 8 , 12 . . . . . . . . 80 Mean, ( x ¯ ) = 4 1 + 2 + 3 + . . . . . . 20 20 = 42 Σ x i 2 = 4 2 1 2 + 2 2 + . . . . . . 20 2 = 16 × 20 × 21 × 41 6 = 4592 0 So, the variance is = Σ x i 2 20 - ( x - ) 2 = 2296 - 1764 = 532

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