InterviewSolution
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InterviewSolution
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A random variable X takes values 1,2,3 and 4 with probabilities `(1)/(6),(1)/(3),(1)/(3),(1)/(6)` respectively, then its mean and variance is equal toA. `5/2,(11)/(12)`B. `5/2,(11)/(16)`C. `5/3,(11)/(16)`D. `5/3,(11)/(12)` |
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Answer» Correct Answer - A Mean `=E(X)=Sigmax_i.P(x_i)=1/6(1)+1/3(2)+1/3(3)+1/6(4)` `=1/6+2/3+1+4/6=(1+4+6+4)/6=(15)/6=5/2` Variance `=Sigmax_i^2.P(x_i)-[E(X)]^2` `=1/6(1)^2+1/3(2)^2+1/3(3)^2+1/6(4)^2-(5/2)^2` `=1/6+4/3+9/3+(16)/6-(25)/4` `=(2+16+36+32-75)/(12)=(86-75)/(12)=(11)/(12)` |
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