Logical Reasoning & Analysis Flashcards

A city installs more streetlights and crime rates drop. A council member concludes that streetlights prevent crime. Which is the best alternative explanation?

Answer: An increased police presence — not the lights — may have reduced crime.

An unmentioned third factor (more police patrols) could explain both why lights were added and why crime fell.

Which of the following most accurately describes a 'necessary condition'?

Answer: Something that must be present for the outcome to occur but does not guarantee it.

A necessary condition must exist for the result to happen, but alone it does not ensure the result occurs.

Two events are positively correlated. Which of the following is the strongest conclusion that can be drawn?

Answer: Events A and B tend to increase and decrease together.

Correlation means the two variables move together but does not establish which, if either, causes the other.

A valid argument is one in which:

Answer: If the premises are true, the conclusion must be true.

Validity is a structural property: a valid argument guarantees the conclusion follows necessarily from true premises.

Which piece of evidence would most directly support the argument that 'exercise improves academic performance'?

Answer: Schools with mandatory gym classes show higher average GPA than those without, controlling for other factors.

Controlled comparison data directly linking exercise programs to higher GPA is the strongest direct evidence for the claim.

Which of the following is an example of a 'false dichotomy'?

Answer: You're either with us or against us — there's no middle ground.

Presenting only two options when more exist (e.g., neutrality, partial agreement) is the false dichotomy fallacy.

A conclusion that 'follows necessarily' from its premises means that:

Answer: The conclusion cannot be false if the premises are true.

Logical necessity means there is no possible scenario where the premises are true and the conclusion is false.