2. The following table summarizes results from an
experiment in which subjects were first classified
as smokers or nonsmokers. After these subjects
were given a treatment, later they were again
classified as smokers or nonsmokers.
After-smoker
After- non-smoker
Before-
smoker
40
14
Before- non-
smoker
5
80
2-1. How many subjects changed their smoking status
after the treatment?
2-2. How many subjects appear to be unaffected by the
treatment?
2-3. Using the appropriate frequencies, find the value of
the test statistic.
2-4. Using a 0.025 significance level, find the critical
value, and make your conclusion.
2-5. Based on the preceding results, do you think this
treatment is really benefit to help people quit
smoking?