if a couple plans to have four children what is the probabil

if a couple plans to have four children, what is the probability that they will have at least one boy

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 < 1) = P(X=0)   
= ( 4 0 ) * 0.5^0 * ( 1- 0.5 ) ^4
= 0.0625
P( X > = 1 ) = 1 - P( X < 1) = 0.9375