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MHT CET202210 Aug 2022Morning ShiftMathematicsProbabilityActual

If p.m.f. of a r.v.X is P(X=x)= 1 10 , for x=1,2,3, , 10=0 , otherwise, then Var (x) is equal to

Options

  1. A11 2
  2. B33 4
  3. C121 4
  4. D77 2

Correct answer

B. 33 4

Step-by-step solution

aligned & Var (x)= P_i x_i^2- ( P_i x_i )^2= 1 10 (1^2+2^2+3^2 .+10^2 ) & - 1 10 (1+2+3+ . .+10) ^2 & = 1 10 10 11 21 6 - ( 1 10 10 11 2 )^2 & =38.5-30.25=8.25= 33 4 aligned

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