Statistics Question

Question

A medication causes headaches as a side effect in 15% of patients who use it. Determine the probability that in a random sample of 20 people exactly 3 patients experience headaches as a side effect.

Answer 1

The number of ways that exactly 3 persons will experience the side effect (headache) is 20C3 = 1140..

 

The probability of this is 1140(0.15)³(0.85)¹⁷= 0.2428.  This is an example of a specific term in a Bernoulli trial/binomial Distribution).