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MHT CET20227 Aug 2022Morning ShiftMathematicsStatisticsActual

If the standard deviation of first n natural numbers is 2 , then the value of n is

Options

  1. A7
  2. B5
  3. C4
  4. D6

Correct answer

A. 7

Step-by-step solution

aligned & S.D. = x_i^2 n -( x )^2 & 2= n^2 n - ( n n )^2 & 4= n(n+1)(2 n+1) 6 n - ( n(n+1) 2 n )^2 & 4= n+1 2 2 n+1 3 - n+1 2 & 4= n+1 2 ( n-1 6 ) & n^2=49 n=7 aligned

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