According to the National Center for Health Statistics, 19.7% of adults are smokers. A random sample of 250 adults is obtained. (a) Describe the sampling distribution of p^, the sample proportion of adults who smoke. (b) In a random sample of 250 adults, what is the probability that at least 50 are smokers? (c) Would it be unusual if a random sample of 250 adults' results in 18% or less being smokers?