A medical researcher says that less than 25% of U.S. adults are smokers. In a random sample of 200 U.S. adults, 19.3% say that they are smokers. At α = 0.05, is there enough evidence to support the researcher’s claim?
(a) Identify the claim and state H0 and Ha,
(b) Find the critical value(s) and identify the rejection region(s),
(c) Find the standardized test statistic z,
(d) Decide whether to reject or fail to reject the null hypothesis,
(e) Interpret the decision in the context of the original claim. If convenient, use technology. |

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