According to the American Lung Association, 90% of adult smokers started smoking before turning 21 years old.
(a) Compute the mean and standard deviation of the random variable X, the number of smokers who started before turning 21 years old in 200 trials of the probability experiment.
(b) Interpret the mean.
(c) Would it be unusual to observe 185 smokers who started smoking before turning 21 years old in a random sample of 200 adult smokers? Why?