Out of 800 families with 5 children each, how many would you expect to have 3 boys? (There are equal chances of occurrence for a boy and a girl.)

• Total number of families=N=800
  Probability of finding a boy=p=1/2
  Probability of finding a girl=q=1-(1/2)
  number of children =n=5
  Number of family expected to have 3 boys (r=3) is
  using binomial distribution,
  P(r) = nCr*q^(n-r)*p^r
  =800*4C2*0.5^2*0.5^3
  =250=ans
• 9 years agoHelpfull: Yes(1) No(3)