SOLUTION: It is known that a certain drug causes side effects in 10% of patients. If we consider a random sampling of 12 patients, what is the probability fewer than two have the side effect

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Question 1157711: It is known that a certain drug causes side effects in 10% of patients. If we consider a random sampling of 12 patients, what is the probability fewer than two have the side effect?
Answer by VFBundy(438) About Me  (Show Source):
You can put this solution on YOUR website!
Probability EXACTLY ONE has the side effect:
%280.1%29%5E1+%2A+%280.9%29%5E11+%2A+%2812%21%2F%281%21%2A11%21%29%29 = 0.1 * 0.3138 * 12 = 0.3766

Probability NONE have the side effect:
%280.9%29%5E12 = 0.2824

Probability FEWER THAN TWO have the side effect: 0.3766 + 0.2824 = 0.6590