Fill in the blanks in the following question:

Let X be a random variable taking values x1, x2,..., xn with probabilities p1, p2, ..., pn, respectively. Then var (X) =

var(X) = E(X2) – [E(X)]2 , where E(X) represents mean or expected value for random variable X


Variance is nothing but the mean of deviation of Random variable from its expected value.


Var(X) = ∑pi(Xi – X)2.


On expanding we get the formula: var(X) = E(X2) – [E(X)]2


Note: You can remember this formula it is a direct formula question.


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