In testing a new drug, researchers found that 5% of all patients using it will have a mild side effect. A random sample of 12 patients using the drug is selected. Find the probability that:

(A) exactly two will have this mild side effect
(B) at least two will have this mild side effect.

Question

In testing a new drug, researchers found that 5% of all patients using it will have a mild side effect. A random sample of 12 patients using the drug is selected. Find the probability that:
 
(A) exactly two will have this mild side effect
(B) at least two will have this mild side effect.

skullpatrol · Answer

Any ideas?

anonymous · Answer

as far as the formula goes i'm figuring its n = 12 and um, p = .05

anonymous · Answer

so i'm under the assumption that i'm working with 12C2(0.05)^2 x .95
or something along those line but i'm not sure how to draw the formula up

skullpatrol · Answer

5% of 12 patients is 0.6

anonymous · Answer

Its A. I think :) 
Binomial Problem with n = 12 ; p = 0.05
P(x=3) = 0.05^3 = 0.125
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(B) at least two will have this mild side effect.
P(2<=x<=12) = 1 - P(0<= x <=1) = 0.1184