Question 45

4. Students use many kinds of criteria when selecting courses. "Lecturer who is a very easy grader" is often one criteria. Three teachers are scheduled to teach Statistics next semester. A sample of the grade distributions for these three lecturers is shown below. Grades Lecturer 1 Lecturer 2 Lecturer 3 A 12 11 27 B 16 29 25 C 35 30 15 Others 27 40 23 Using the 0.01 level of significance, test the hypothesis "Student's grades are independent of the student's lecturer." a) State the null and alternative hypothesis for a test of independent between grades and lecturer. b) Determine the test criteria: test statistics and critical region. c) State the decision and conclusion. 5. Boles and Johnson examined the beliefs held by adolescents regarding smoking and weight. Respondents characterized their weight into three categories: underweight, overweight, or appropriate. Smoking status was categorized according to the answer to the question, "Do you currently smoke, meaning one or more cigarettes per day?" The following table shows the results of a telephone study of adolescents in the age group 12-17. Smoking Yes No Underweight 17 97 Overweight 25 142 Appropriate 96 816 Do the data provide sufficient evidence to suggest that weight perception and smoking status are related in adolescents? A = 0.05