A. ARQ chapter 9, “Are There Rival Causes?”:

1. Rival causes are alternative reasonings that can explain an outcome that occurred. When looking at data or evidence, it is important to look for rival causes because there usually can be more than one reason for an outcome. One question you should ask is “Are there any alternative ways to interpret the evidence?” Another question is “What are other causes are important from a different point of view?”
2. Causation is the idea of cause and effect. For example, when the temperature rises, the sale of ice cream also rises. The cause is the rise in temperature and the sale of ice cream is the effect. Association or correlation is a relationship between two or more variables. For example, there is a correlation between ice cream sales and drowning accidents. The two variables are not related, but have a positive correlation, or relationship. This can be explained by other factors, such as the rise in temperature. Higher temperatures often lead to more ice cream sales and more people swimming. Association/correlation is more difficult to demonstrate because often there is a third variable (like temperature creates a rise in ice cream sales and drownings) connecting two unrelated variables. This third variable is frequently left out, leading to a fallacy.
3. Identify the conclusion and reason (cause) for the conclusion in the following passage. Name two potential rival causes (other possible causes) for the conclusion other than the one given.

Increased amounts of germs and bacteria on college campuses cause higher rates of illness in college students. College students are less likely to sanitize living areas and common areas on campus, which in turn creates excessive germs on surfaces and in the air leading to more sickness in students.

• Conclusion: Increased amounts of germs and bacteria cause higher rates of illness in college students.
• Reason/cause: College students are less likely to sanitize living areas and common areas on campus.
• Rival (other possible) causes: College students have a poor diet, which effects the immune system. Students may have underlying heath problems and being a new environment can lead to less doctor visits and an increase of stress, both of which can lead to more sickness.
• Evaluation (How strong is the original argument? What’s missing?): The original argument is good, but there are rival causes that can also be used to argue why college students have a higher rate of illness.

B. Based on your reading of ARQ chapter 10, “Are Any Statistics Deceptive?”, summarize how the following types of statistics can be deceptive. What are some strategies you can use to determine how reliable each type is?

• Unknowable and biased statistics: Finding out how the data was collected and how the statistics were interpreted is important in determining how reliable the statistics are.
• Confusing averages: Averages can be different types. It can be a mean, which is adding all the values together and dividing by the number of values. The median is the middle value point. And the mode is the most frequent values. Each type of average can be different for one set of values.
• Measurement errors: Measurement errors are problems that occur when gather data. This can include equipment that is not calibrated, time lapses in between measurements, and temperature differences.
• Concluding one thing, proving another: You can determine the reliability of the conclusion by blinging yourself from the person’s statistics and by paying attention to the wording of the statistic and that of the conclusion. If the wording of the two are different, than the conclusion is not reliable.
• Deceiving by omitting information: By figuring out what information is needed in order to understand the statistics to the full extent, you can also figure out how deceiving the statistic or information is. For example, absolute numbers are more deceiving than percentages in some cases.

C. Read the following passage. Identify the conclusion, and reasons, and evaluate the evidence (in this case the statistics) used to support the writer’s argument.

The home is becoming a more dangerous place to spend time. The number of home-related injuries is on the rise. In 2005, approximately 2300 children aged 14 and under died from accidents in the home. Also, 4.7 million people are bitten by dogs each year. To make matters worse, even television, a relatively safe household appliance, is becoming dangerous. In fact, 42,000 people are injured by televisions and television stands each year. With so many accidents in the home, perhaps people need to start spending more time outdoors.

• Conclusion: Homes are becoming increasingly dangerous.
• Reasons/causes: There is an increased number of home-related injuries, including injuries caused by televisions and dog bites. There are also adolescent deaths from accidents within the home.
• Evaluate the evidence (the statistics): For the 2,300 children that have died from accidents at home, a percentage would be more appropriate so that the actual value of deaths is accurately represented. The statistic for the number of people who are bitten by dogs could also include people who receive dog bites outside of the home, like in a park. The number of people injured by televisions and TV stands would be better as a percentage for the same reason as the statistic for children’s deaths. Absolute numbers are deceiving for statistics because the use of numbers seem to be more alarming than percentages.