jenzy569
Junior Member
USA
4 Posts 
Posted  10/26/2011 : 18:24:44

In testing a new drug, researchers found that 10% of all patients using it will have a mild side effect. A random sample of 14 patients using the drug is selected. Find the probability that: (A) exactly two will have this mild side effect (B) at least three will have this mild side effect.
N = 14 (14 patients) X = 2 (exactly 2 will have this mild side effect) P = 0.10 (prob. of all patients using it will have a mild side effect; success) Q = 0.90 (1  p = 1  0.10 = 0.9)
(A) = 14!/(142)!2! (0.10)²(0.90)142^2 = 14*13*12!/12!2*1(0.10)²(0.90)12^2 = 14*13/2*1(0.01)(0.28) = 182/2(0.01)(0.28) = 91(0.01)(0.28) = 0.25 or 25%
But I'm not sure how to do part B.....please help!!


