SOLUTION MANUAL for ELEMENTARY STATISTICS THIRTEENTH EDITION by Mario F. Triola

SOLUTION MANUAL for ELEMENTARY STATISTICS THIRTEENTH EDITION by Mario F. Triola Chapter 1: Introduction to Statistics Section 1-1: Statistical and Critical Thinking 1. The respondents are a voluntary response sample or ...

SOLUTION MANUAL for ELEMENTARY STATISTICS THIRTEENTH EDITION by Mario F. Triola Chapter 1: Introduction to Statistics Section 1-1: Statistical and Critical Thinking 1. The respondents are a voluntary response sample or a self-selected sample. Because those with strong interests in the topic are more likely to respond, it is very possible that their responses do not reflect the opinions or behavior of the general population. 2. a. The sample consists of the 1046 adults who were surveyed. The population consists of all adults. b. When asked, respondents might be inclined to avoid the shame of the unhealthy habit of not washing their hands, so the reported rate of 70% might well be much higher than it is in reality. It is generally better to observe or measure human behavior than to ask subjects about it. 3. Statistical significance is indicated when methods of statistics are used to reach a conclusion that a treatment is effective, but common sense might suggest that the treatment does not make enough of a difference to justify its use or to be practical. Yes, it is possible for a study to have statistical significance, but not practical significance. 4. No. Correlation does not imply causation. The example illustrates a correlation that is clearly not the result of any interaction or cause effect relationship between deaths in swimming pools and power generated from nuclear power plants. 5. Yes, there does appear to be a potential to create a bias. 6. No, there does not appear to be a potential to create a bias. 7. No, there does not appear to be a potential to create a bias. 8. Yes, there does appear to be a potential to create a bias. 9. The sample is a voluntary response sample and has strong potential to be flawed. 10. The samples are voluntary response samples and have potential for being flawed, but this approach might be necessary due to ethical considerations involved in randomly selecting subjects and somehow imposing treatments on them. 11. The sampling method appears to be sound. 12. The sampling method appears to be sound. 13. With only a 1% chance of getting such results with a program that has no effect, the program appears to have statistical significance. Also, because the average loss of 22 pounds does seem substantial, the program appears to also have practical significance. 14. Because there is a 0.3% chance of getting such results by chance, the increase in scores does appear to have statistical significance. The typical increase of 5 points suggests that the course does have practical significance. The course does appear to be successful. 15. Because there is a 19% chance of getting that many girls by chance, the method appears to lack statistical significance. The result of 1020 girls in 2000 births (51% girls) is above the approximately 50% rate expected by chance, but it does not appear to be high enough to have practical significance. Not many couples would bother with a procedure that raises the likelihood of a girl from 50% to 51%. 16. Because there is a 25% chance of getting such results with a program that has no effect, the program does not appear to have statistical significance. Because the average increase is only 3 IQ points, the program does not appear to have practical significance. 17. Yes. Each column of 8 AM and 12 AM temperatures is recorded from the same subject, so each pair is matched. 18. No. The source is from university researchers who do not appear to gain from distorting the data. 19. The data can be used to address the issue of whether there is a correlation between body temperatures at 8 AM and at 12 AM. Also, the data can be used to determine whether there are differences between body temperatures at 8 AM and at 12 AM. 20. Because the differences could easily occur by chance (with a 64% chance), the differences do not appear to have statistical significance. 21. No. The white blood cell counts measure a different quantity than the red blood cell counts, so their differences are meaningless. VERIFIEDBRAINBOOSTER VERIFIEDBRAINBOOSTER 2 Elementary Statistics, 13th edition Copyright © 2018 Pearson Education, Inc. 22. The issue that can be addressed is whether there is a correlation, or association, between white blood cell counts and red blood cell counts. 23. No. The National Center for Health Statistics has no reason to collect or present the data in a way that is biased. 24. No. Correlation does not imply causation, so a statistical correlation between white blood cell counts and red blood cell counts should not be used to conclude that higher white blood cell counts are the cause of higher red blood cell counts. 25. It is questionable that the sponsor is the Idaho Potato Commission and the favorite vegetable is potatoes. 26. The sample is a voluntary response sample, so there is a good chance that the results do not reflect the larger population of people who have a water preference. 27. The correlation, or association, between two variables does not mean that one of the variables is the cause of the other. Correlation does not imply causation. Clearly, sour cream consumption is not directly related in any way to motorcycle fatalities. 28. The sponsor of the poll is an electronic cigarette maker, so the sponsor does have an interest in the poll results. The source is questionable. 29. a. 700 adults b. 55% 30. a. 253.31 subjects b. No. Because the result is a count of people among the 347 who were surveyed, the result must be a whole number. c. 253 subjects d. 32% 31. a. 559.2 respondents b. No. Because the result is a count of respondents among the 1165 engaged or married women who were surveyed, the result must be a whole number. c. 559 respondents d. 8% 32. a. 293.17 women b. No. Because the result is a count of women among the 1543 who were surveyed, the result must be a whole number. c. 293 women d. 15% e. Interpretations of a “typical” week and what it means to “kick back and relax” might vary considerably by different survey respondents. The survey might be improved by asking about behavior within “the past seven days” instead of a “typical” week. Instead of “kick back and relax,” respondents might be surveyed about specific behavior, such as reading, taking a nap, watching television, listening to music, or going for a walk. 33. Because a reduction of 100% would eliminate all of the size, it is not possible to reduce the size by 100% or more. 34. In an editorial criticizing the statement, the New York Times correctly interpreted the 100% improvement to mean that no baggage is being lost, which was not true. 35. Because a reduction of 100% would eliminate all plaque, it is not possible to reduce it by more than 100%. 36. If one subgroup receives a 4% raise and another subgroup receives a 4% raise, the combined group will receive a 4% raise, not an 8% raise. The percentages should not be added in this case. 37. The wording of the question is biased and tends to encourage negative responses. The sample size of 20 is too small. Survey respondents are self-selected instead of being randomly selected by the newspaper. If 20 readers respond, the percentages should be multiples of 5, so 87% and 13% are not possible results. 38. All percentages of success should be multiples of 5. The given percentages cannot be correct.