Question 186298
how do i solve this In testing a new drug, researchers found that 5% of all patients using it will have a mild side effect. A random sample of 11 patients using the drug is selected. Find the probability that: 
a) exactly two will have this mild side effect
b) at least one will have this mild side effect.
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It's a binomial problem with n=11 and p = 0.05
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a) P(exactly two will have this mild side effect) = 11C2(0.05)^2*(0.95)^9
= 55* 0.0025* 0.6302 = 0.0867
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b) P(at least one will have this mild side effect)
= 1 - P(none have the effect)
= 1 - 11C0*(0.05)^0*0.95*11 = 1-0.95^11 = 0.4312
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Cheers,
Stan H.