Question 737485
This is a binomial distribution with n=4, p=.50 and you want
{{{P(x>=2).}}}

{{{P(x>=2)=P(x=2)+P(x=3)+P(x=4)=((4!)/(2!2!))(.5)^2(.5)^2+((4!)/(3!1!))(.5)^3(.5)^1+((4!)/(4!0!))(.5)^4(.5)^0}}}
{{{6(.5)^4+4(.5)^2(.5)^2+1(.5)^4= .3750+.2500+.0625=.6875}}}