SOLUTIONS MANUAL FOR USING AND UNDERSTANDING MATHEMATICS A QUANTITATIVE REASONING APPROACH EIGHTH EDITION

SOLUTIONS MANUAL FOR USING AND UNDERSTANDING MATHEMATICS A QUANTITATIVE REASONING APPROACH EIGHTH EDITION-Pg. 21. Not guilty does not mean innocent; it means not enough evidence to prove guilt. If defendants were required to prove innocence, there would be many cases where they would be unable to provide such proof even though they were, in fact, innocent. This relates to the fallacy of appeal to ignorance in the sense that lack of proof of guilt does not mean innocence, and lack of proof of innocence does not mean guilt. Pg. 23. Opinions will vary. One argument is that character questions should be allowed in court if answers to those questions may show bias or ulterior motives for testimony given by a witness. This would be a good topic for a discussion either during or outside of class. QUICK QUIZ QQ1. a. By the definition used in this book, an argument always contains at least one premise and a conclusion. QQ2. c. By definition, a fallacy is a deceptive argument. QQ3. b. An argument must contain a conclusion. QQ4. a. Circular reasoning is an argument where the premise and the conclusion say essentially the same thing. QQ5. b. Using the fact that a statement is unproved to imply that it is false is appeal to ignorance. QQ6. b. “I don’t support the President’s tax plan” is the conclusion because the premise “I don’t trust his motives” supports that conclusion. QQ7. b. This is a personal attack because the premise (I don’t trust his motives) attacks the character of the President, and says nothing about the substance of his tax plan. QQ8. c. This is limited choice because the argument does not allow for the possibility that you are a fan of, say, boxing. QQ9. b. Just because A preceded B does not necessarily imply that A caused B. QQ10. a. By definition, a straw man is an argument that distorts (or misrepresents) the real issue. READING QUESTIONS 1. Logic is the study of the methods and principles of reasoning. Arguing logically may or may not change a person’s position, but it can give either person insight into the other’s thinking. 2. An argument refers to a reasoned or thoughtful process. An argument uses a set of facts or assumptions, called premises, to support a conclusion. 3. A fallacy is an argument in which the conclusion is not well supported by the premises. The examples of fallacies given in the text are appeal to popularity, false cause, appeal to ignorance, hasty generalization, limited choice, appeal to emotion, personal attack, circular reasoning, diversion (red herring), and straw man. Examples will vary. 4. The five steps (See the information box on page 24 in the text for a summary of each step.) to evaluating media information are: 1. Consider the source. 2. Check the date. 3. Validate accuracy. 4. Watch for hidden agendas. 5. Don’t miss the big picture. DOES IT MAKE SENSE? 5. Does not make sense. Raising one’s voice has nothing to do with logical arguments. 6. Does not make sense. Logical arguments always contain at least one premise and a conclusion. 7. Makes sense. A logical person would not put much faith in an argument that uses premises he believes to be false to support a conclusion. 2 CHAPTER 1: THINKING CRITICALLY 8. Makes sense. There’s nothing wrong with stating the conclusion of an argument before laying out the premises. 9. Does not make sense. One can disagree with the conclusion of a well-stated argument regardless of whether it is fallacious. 10. Makes sense. Despite the fact that an argument may be poorly constructed and fallacious, it still may have a believable conclusion. BASIC SKILLS AND CONCEPTS 11. a. Premise: Apple’s iPhone outsells all other smartphones. Conclusion: They must be the best smartphone on the market. b. The fact that many people buy the iPhone does not necessarily mean it is the best smartphone. 12. a. Premise: I became sick soon after eating at Burger Hut. Conclusion: Burger Hut food made me sick. b. The argument doesn’t prove that Burger Hut food was the cause of the sickness. 13. a. Premise: Decades of searching have not revealed life on other planets. Conclusion: Life in the universe must be confined to Earth. b. Failure to find life on other planets does not imply that life does not exist elsewhere in the universe. 14. a. Premise: I saw three people use food stamps to buy expensive steaks. Conclusion: Abuse of food stamps is widespread. b. The conclusion is based on relatively little evidence. 15. a. Premise: He refused to testify by invoking his Fifth Amendment rights. Conclusion: He must be guilty. b. There are many reasons that someone might have for refusing to testify (being guilty is only one of them), and thus this is the fallacy of limited choice. 16. a. Premise: Thousands of unarmed people, many of them children, are killed by firearms every year. Conclusion: The sale of all guns should be banned. b. The conclusion is reached on the basis of an emotional statement. 17. a. Premise: Senator Smith has accepted contributions from companies that sell genetically modified crop seeds. Conclusion: Senator Smith’s bill is a sham. b. A claim about Senator Smith’s personal behavior is used to criticize his bill. 18. a. Premise: It's illegal to drive faster than the speed limit and breaking the law makes you a criminal. Conclusion: Drivers who exceed the speed limit are criminals. b. The conclusion is a restatement of the premise. 19. a. Premise: Good grades are needed to get into college, and a college diploma is necessary for a good career. Conclusion: Attendance should count in high school grades. b. The premise (which is often true) directs attention away from the conclusion. 20. a. Premise: The mayor wants to raise taxes to fund social programs. Conclusion: She must not believe in the value of hard work. b. The mayor is characterized (perhaps wrongly) by one quality, on which the conclusion is based. 21. false; Explanations will vary. 22. false; Explanations will vary. FURTHER APPLICATIONS 23. false; Explanations will vary. 24. true; Explanations will vary. 25. Premise: Eating oysters for dinner, followed by a nightmare. Conclusion: Oysters cause nightmares. This argument suffers from the false cause fallacy. We cannot conclude that the former caused the latter simply because they happened together.