Question: Smoking in the United States. Carry out the significance test called for in Exercise I in all detail. Show the five steps of the test (hypotheses, sampling distribution, data, P-value, conclusion) clearly.
Exercise I: Smoking in the United States. Does the survey of Exercise II provide good evidence that fewer than 1/4 of all American adults smoked in the week prior to the survey?
(a) State the hypotheses to be tested.
(b) If your null hypothesis is true, what is the sampling distribution of the sample proportion ? Sketch this distribution.
(c) Mark the actual value of on the curve. Does it appear surprising enough to give good evidence against the null hypothesis?
Exercise II: Smoking in the United States. An August 2007 nationwide random survey of 1012 adults asked whether they had smoked cigarettes in the last week. Among the respondents, 243 said they had. We can act as if the sample were an SRS.
(a) Give a 95% confidence interval for the proportion of all American adults who smoked in the week preceding the survey.
(b) Write a short paragraph for a news report based on the survey results.