Question: Smoking by students and their families. In Exercise, you saw that there is an association between smoking by close family members and smoking by high school students. The students are more likely to smoke if a close family member smokes. We want to know whether this association is statistically significant.
(a) State the hypotheses for the chi-square test. What do you think the population is?
(b) Find the expected cell counts. Write a sentence that explains in simple language what "expected counts" are.
(c) Find the chi-square statistic and its degrees of freedom. What is your conclusion about significance?
Exercise: Smoking by students and their families. How are the smoking habits of students related to the smoking habits of their close family members? Here is a two-way table from a survey of male students in six secondary schools in Malaysia:
Student Student
smokes does not smoke
At least one close family member smokes 115 207
No close family member smokes 25 75
Write a brief answer to the question posed, including a comparison of selected percentages.