seven percent of the people in Kenya have type o negative .You randomly selected 30 people .Find the probability that:
1.0 exactly 4 people say are -o
2.0 At least
n=30
p=0.07
q=0.93
mean=30*0.07=2.1
std=sqrt(npq)=sqrt(300.070.93)=1.4
that is exactly between 3.5 and 4.5 –correction for continuity
x=3.5
then z=(x-mean)/std =(3.5-2.1)/1.4 =1
x=4.5 then Z =(4.5-2.1)/1.4 =1.71
THEREFORE Z lies between 1 and 1.71