Answer:
Step-by-step explanation:
This is a binomial probability problem. There are only two outcomes. It is either a chosen person has immunity to a particular disease or he does not. The probability of success in this case, p is the probability that a chosen person has immunity to a particular disease. Thus
p = 0.6
The probability of failure, q is q = 1 - p
Thus, q = 1 - 0.6 = 0.4
Mean = np
Where n represents sample size. Thus,
Mean = 12 × 0.6 = 7.2
