Two cards are drawn from a well-shuffled pack of 52 cards. Find the probability distribution of a number of kings. Also, compute the variance for the number of kings. [CBSE 2007]

Given : Two cards are drawn from a well-shuffled pack of 52 cards.


To find : probability distribution of the number of kings and variance (σ2)


Formula used :



Mean = E(X) =


Variance = E(X2) -


Mean = E(X) = = x1P(x1) + x2P(x2) + x3P(x3)


Two cards are drawn from a well-shuffled pack of 52 cards.


Let X denote the number of kings in the two cards


There are 4 king cards present in a pack of well-shuffled pack of 52 cards.


P(0) = = =


P(1) = = =


P(2) = = =


The probability distribution table is as follows,



Mean = E(X) = 0() + 1() +2() = 0 + + = =


Mean = E(X) =


= =


E(X2) = = P(x1) + P(x2) + P(x3)


E(X2) = () + () + () = 0 + + =


E(X2) =


Variance = E(X2) - = = = =


Variance = E(X2) - =


The probability distribution table is as follows,



Variance =


1