The Little Blue Reasoning Book - Brandon Royal [43]
All physics students study math.
Most math students are also studying English.
Some English students also study creative writing.
If the statements above are true, which of the following must be false?
A) Some creative writing students also study French.
B) All physics students also study English.
C) All math students also study physics.
D) Some, but not most English students also study math.
E) Some physics students also study French.
See solution
Appendixes
Nothing hath an uglier look
to us than reason,
when it is not of our side.
—Halifax
APPENDIX I – SUMMARY OF REASONING TIPS 1 TO 50
Chapter 1: Perception & Mindset
Tip #1: Selective perception is the tendency to see the world the way we would like it to be rather than how it really is. The sound thinker suspends judgment and is not unduly influenced by stereotypes, prejudices, isolated experiences, or preconceived notions.
Tip #2: Think of mindsets as divided into four basic types: Analysts, Idealists, Realists, and Synthesists. These mindsets can be further contrasted based on levels of practicality and emotional attachment.
Chapter 2: Creative Thinking
Tip #3: Creative thinking is “backdoor” thinking.
Tip #4: Convergent thinking focuses the mind; divergent thinking opens the mind.
Tip #5: The devil’s advocate technique imposes objectivity and compels divergent thinking.
Tip #6: Not challenging the obvious, evaluating ideas too quickly, and fear of looking the fool — these are the three greatest creativity inhibitors.
Tip #7: Keep a mental list of idea “killers” and idea “growers.”
Tip #8: Brainstorming has rules: quantity of ideas is preferred, wacky ideas are welcome, delayed evaluation is mandatory, and “hitchhiking” is encouraged.
Tip #9: Consider whether a problem is really the problem. Think in terms of redefining the problem.
Tip #10: Prisoner’s Dilemma provides an example of how cooperation is superior to competition.
Tip #11: In selling creative ideas, most people are moved more by the depth of a person’s conviction and commitment than they are by the details of a logical presentation.
Chapter 3: Decision Making
Tip #12: Pros-and-cons analysis may be illustrated using a “T-Account,” with pros on one side and cons on the other side.
Tip #13: A matrix is a useful tool to summarize data that can be contrasted across two variables and sorted into four distinct outcomes.
Tip #14: Decision-event trees are a way to represent graphically the multiple outcomes involved in a decision scenario.
Tip #15: The end branches of a probability tree must total to 1, which is equal to the aggregate of all individual probabilities.
Tip #16: Weighted ranking is a tool for finding solutions using a weighted average. To calculate weighted average, we multiply each event by its associated weight and total the results. In the case of probabilities, we multiply each event by its respective probability and total the results.
Tip #17: Utility analysis takes into account desirability of outcomes, which may be different from monetary payoffs.
Tip #18: For the purposes of hypothesis testing, the minimum requirement for causal inference is evaluation using a “two-way” table.
Chapter 4: Analyzing Arguments
Tip #19: Evidence + Assumption = Conclusion. The assumption is the glue that holds the evidence to the conclusion.
Tip #20: There are effectively two ways to attack an argument: attack the evidence or attack the assumption(s).
Tip #21: The five most common critical reasoning errors people make include: comparing “apples with oranges,” overgeneralizing on the basis of small samples, ignoring relevant evidence, confusing cause and effect, and failing to anticipate bottlenecks when plans are put into action.
Tip #22: Watch for “scope shifts,” which occur when one term is substituted for another as an argument unfolds.
Tip #23: Changes in definition destroy the ability to make valid comparisons
Tip #24: If a situation involves a “survey,