91 of Dr Williams patients end up with 2030 vision or better
91% of Dr. William\'s patients end up with 20-30 vision or better. Find the probability that exactly 4 of her next 6 patients with 20-30 vision or better .
Solution
Given X follows Binomial distribution with n=6 and p=0.91
P(X=x)=6Cx*(0.91^x)*(0.09^(6-x)) for x=0,1,2,...,6
So the probability is
P(X=4)=6C4*(0.91^4)*(0.09^(6-4)) =0.0833
