Question 611582:  In testing a new drug, researchers found that 5% of all patients using it will have a mild side effect. A random sample of 13 patients using the drug is selected. Find the probability that:  
  
(A) exactly three will have this mild side effect 
(B) at least two will have this mild side effect.  
 
 Answer by stanbon(75887)      (Show Source): 
You can  put this solution on YOUR website! In testing a new drug, researchers found that 5% of all patients using it will have a mild side effect. A random sample of 13 patients using the drug is selected.  
Binomial Problem with n = 13 and p(side effect) = 0.05 
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Find the probability that: 
 
(A) exactly three will have this mild side effect 
P(x = 3) = 13C3*0.05^3*(0.95)^0 = 0.02140 
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(B) at least two will have this mild side effect. 
P(2<= x <=3) = 1 - binomcdf(13,0.05,1) = 0.1354 
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Cheers, 
Stan H. 
 
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