10.2 EXERCISES 542 CHAPTER 10 Chi-Square Tests and the F-Distribution For Extra Help: MyLab Statistics Building Basic Skills and Vocabulary 1. Explain how to find the expected frequency for a cell in a contingency table. 2. Explain the difference between marginal frequencies and joint frequencies in a contingency table. 3. Explain how the chi-square independence test and the chi-square goodness-of-fit test are similar. How are they different? 4. Explain why the chi-square independence test is always a right-tailed test. True or False? In Exercises 5 and 6, determine whether the statement is true or false. If it is false, rewrite it as a true statement. 5. If the two variables in a chi-square independence test are dependent, then you can expect little difference between the observed frequencies and the expected frequencies. 6. When the test statistic for the chi-square independence test is large, you will, in most cases, reject the null hypothesis. Finding Expected Frequencies In Exercises 7–12, (a) calculate the marginal frequencies and (b) find the expected frequency for each cell in the contingency table. Assume that the variables are independent. 7. Athlete has Result Stretched Not stretched Injury 18 22 No injury 211 189 8. Treatment Result Drug Placebo Nausea 36 13 No nausea 254 262 9. Preference Bank employee New procedure Old procedure No preference Teller 92 351 50 Customer service representative 76 42 8 10. Rating Size of restaurant Excellent Fair Poor Seats 100 or fewer 182 203 165 Seats over 100 180 311 159 11. Type of car Gender Compact Full-size SUV Truck/van Male 28 39 21 22 Female 24 32 20 14
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