Question 1151501
This is a binomial distribution with n=5 and p=0.25
probability of 0 people being low is 0.75^5=0.2373
of 1 is 5*0.25*0.75^4=0.3955
Of 2 is 5C2*0.25^2*0.75^3=10*0.0625*.75^3=0.2637
of 3 is 10*0.25^3*0.75^2=0.0879
of 4 is 5*.25^4*.75=0.0146
of 5 is 0.25^5=0.001

at least 2 is 1-P(0,1)=1-0.6328=0.3672
at most 3 is P(0,1,2,3)=0.9844
E(X)=np=1.25
V(X)=np(l-p)=1.25*0.75=0.9375