1. AP Statistics Section 14.2 B

2. We can use the chi-square test of association/independence to test the null hypothesis when you have a two-way table from a single SRS, with each individual classified according to both of two categorical variables.

3. Example: North Carolina State University studied student performance in a course required for its chemical engineering major. One question of interest is the relationship between time spent in extracurricular activities and whether a student earned a C or better in the course. Here are the data for 119 students who answered a question about extracurricular activities.

4. Grade< 22 to 12>12 C or better 11 68 3 D or F 9 23 5

5. a) Find the proportion of students (C or better) in each of the three extracurricular activity groups. What do these proportions show?

6. b) Carry out an appropriate significance test. Hypothesis: The population of interest is _____________________________________________ H 0 : __________________________________________ H a : __________________________________________

7. Conditions:

8. Calculations:

9. Conclusions:

10. c) Does the study convince you that there is a relationship between the amount of time spent in extracurricular activities and academic performance in this course?