Two years ago, a complete survey of all students in a large university indicated that the mean number of cigarettes smoked per day by male students was 8.3 with a standard deviation of 3.7.The director of student health services wishes to determine whether or not smoking habits among male students at the university have changed over the 2-year period. She obtains the following results for the men from a recently selected random sample of students (in cigarettes smoked per day): X 7.7, n 108.
(a) Set up H0 and HA.
(b) Perform the statistical test (.05).
(c) Draw final conclusions.