Three in five adults in the U.S. own an answering machine. In a random sample of 12 adults, what is the probability that the number owning answering machine is:
A) exactly nine,
B) at least nine,
C) What is the expected value of the random variable defined in this problem?
Let X be the number out of 12 adults that own an answering machine. Based on the information given by the problem, X ~ binomial(12, 3/5) = binomial(12, 0.6)
For a ...
This solution shows how to calculate the given probability questions.