Question 639337
a. {{{P(X = 4) = (matrix(2,1,12,4))(0.3^4)(0.7^8) = highlight(0.23114)}}}
b. {{{P(X <= 4) = sum((matrix(2,1,12,x))(0.3^x)(0.7^(12-x)),x=0,4)}}}
c. µ = np = 12(0.3) = 3.6
  and &#963; = {{{sqrt(npq) = sqrt((12)(0.3)(0.7)) = 1.58745}}}
  {{{P(X = 4)= P(3.5 <= X <= 4.5)}}}
   &#8776;{{{ P((3.5-3.6)/1.58745 <= Z <= (4.5-3.6)/1.58745)}}}