It is believed that the probablility of serving an ace in te
It is believed that the probablility of serving an ace in tennis on any given serve is 0.2. If a tennis player serves 8 times, what is the probablility that he makes an ace on at least 2 of the 8 serves?
 It is believed that the probablility of serving an ace in tennis on any given serve is 0.2. If a tennis player serves 8 times, what is the probablility that he makes an ace on at least 2 of the 8 serves?
Solution
Binomial Distribution
PMF of B.D is = f ( k ) = ( n k ) p^k * ( 1- p) ^ n-k
 Where   
 k = number of successes in trials
 n = is the number of independent trials
 p = probability of success on each trial
 P( X < 2) = P(X=1) + P(X=0)
 = ( 8 1 ) * 0.2^1 * ( 1- 0.2 ) ^7 + ( 8 0 ) * 0.2^0 * ( 1- 0.2 ) ^8
 = 0.5033
 P( X > = 2 ) = 1 - P( X < 2) = 0.4967

