Question

Ex 2

Definition: A random variable X is said to have a binomial distribution and is referred to as a binomial random variable, if and only if its probability distribution is given by P(X-x)"C.pq" for x -0, 1,2,.., If X~B (n, p), then . E(X)= np and Var(X)=np(1-p) Notation for the above definition: n number of trials xnumber of success among n trials p probability of success in any one trial q probability of failure in any one trial Example 2: In the instant lottery with 20% winning tickets, eight such tickets are purchased. Find the probability for the following outcomes: (i) 2 tickets are winning tickets (ii) 2 tickets are losing tickets.