Logical Reasoning

Directions: Indicate whether the following arguments are deductive or inductive. If the argument is deductive, specify whether it is valid or invalid, sound or not sound. If it is inductive, specify whether it is strong or weak, cogent or not cogent. (6 pts.)

1. Gas-powered cars require gas in order to start. My car's gas tank is empty. Therefore, my car will not start.

2. All people who wear tight jeans are hipsters. All people who collect vinyl records are hipsters. Hence, all people who wear tight jeans collect vinyl records.

3.In a random sample of 380,000 freshmen at 722 four-year colleges, 25% said they often came to class without completing readings or assignments. We can thus conclude that there is a 95% chance that between 24% and 26% of all college freshmen come to class unprepared.

4. People try on shoes before buying them. People drive cars before signing up for a three-year lease. People take a close look at travel information before committing to an expensive vacation.

Similarly, people should have sex before getting married.

5. No one has yet proven that there is an objective basis for determining whether an action is morally right or wrong (i.e., no one has yet proven that universal moral standards exist - e.g., a prohibition against killing... humans, animals). Thus, there is no objective basis for determining whether an action is morally right or wrong. (i.e., any such basis for determining the morality of an action is always personally or culturally relative, otherwise known as "moral relativism").

6. Give an example of a decision that you recently made in which the method of reasoning you used to reach the decision was induction. Describe your reasoning process.

Statistical Arguments

Directions: Read the following passage and then decide whether the following arguments reason from a sample to a population, a population to a sample, or a sample to a sample. (4 pts.)

In the midst of a budgetary crisis, administrators at Central University decide that they must either increase fees by 35% or increase class sizes and limit course offerings. Students are asked which option they prefer. There is a sharp difference of opinion.

7. The student body is generally opposed to a major fee increase. 65 students are asked about the fee increase. Based on the sentiment of the student body, it is likely that most of the students in the survey will oppose a major fee increase.

8. A questionnaire was given to 40 students from various departments and years. 32 said they were opposed to a major fee increase. So, most students are opposed to a major fee increase.

9. The student body as a whole is strongly opposed to a major fee increase. So, there is a good chance that the next students we ask will also oppose a major fee increase.

10. A survey was given to 40 students from various departments and years. 32 said they were opposed to a major fee increase. So, the next student will likely oppose a major fee increase.