CHAPTER 9 Review Exercises 499 4. Confidence Interval When using the given sample results and the claim given in Exercise 1, the 95% confidence interval of 10.00732, 0.1592 is obtained. a. Express the confidence interval in the format of an inequality that uses the symbol 6 . b. What feature of the confidence interval is a basis for deciding whether there is a significant difference between the success rate in the treatment group and the success rate in the placebo group? 5. Coke and Diet Coke Data Set 37 “Cola Weights and Volumes” in Appendix B includes the weights (in pounds) of cola for a sample of cans of regular Coke 1n = 36, x = 0.81682 lb, s = 0.00751 lb2 and the weights of cola for a sample of cans of Diet Coke 1n = 36, x = 0.78479 lb, s = 0.00439 lb2. a. Are the two samples independent or are they dependent? Explain. b. If we want to test the claim that the weights of regular Coke and the weights of Diet Coke have the same mean, what is the value of the test statistic? 6. Variation Find the value of the test statistic used for testing the claim that the two samples from Exercise 5 are from populations having the same variation. 7.Body Temperatures Listed below are body temperatures from six different subjects measured at two different times in a day (from Data Set 5 “Body Temperatures” in Appendix B). a. Are the two sets of data independent or dependent? Explain. b. Identify the null and alternative hypotheses for using the sample data to test the claim that the differences between 8 AM temperatures and 12 AM temperatures are from a population with a mean equal to 0°F. Temperature 1 °F2 at 8 AM 98.2 97.4 97.8 98.4 97.6 96.2 Temperature 1 °F2 at 12 AM 98.0 98.2 98.0 98.0 97.0 97.2 8.Body Temperatures Technology is used to test the claim that for the sample data from Exercise 7, the differences between 8 AM temperatures and 12 AM temperatures are from a population with a mean equal to 0°F. Technology provides this 95% confidence interval: -0.82°F 6 md 6 0.55°F. What does this confidence interval suggest about the data? 9. True? Determine whether the following statement is true: When random samples of 250 men and 250 women are obtained and we want to test the claim that men and women have the same mean SAT scores, there is no need to confirm that the samples are from populations with normal distributions. 10. True? When we collect random samples to test the claim that the proportion of female statistics professors is equal to the proportion of female physics professors, there is a requirement that np Ú 30 and nq Ú 30. 1.Denomination Effect In the article “The Denomination Effect” by Priya Raghubir and Joydeep Srivastava, Journal of Consumer Research, Vol. 36, researchers reported results from studies conducted to determine whether people have different spending characteristics when they have larger bills, such as a $20 bill, instead of smaller bills, such as twenty $1 bills. In one trial, 89 undergraduate business students from two different colleges were randomly assigned to two different groups. In the “dollar bill” group, 46 subjects were given dollar bills; the “quarter” group consisted of 43 subjects given quarters. All subjects from both groups were given a choice of keeping the money or buying gum or mints. The article includes the claim Review Exercises
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