CCTST Deductive Reasoning 5

Question 1

The argument form 'P → Q; P; therefore Q' is called:

Accepted Answer

Modus ponens

Answer

Modus ponens (affirming the antecedent) concludes Q when both P→Q and P are given.

Question 2

Some athletes are vegetarians. All vegetarians avoid red meat. Which conclusion must be true?

Accepted Answer

Some athletes avoid red meat

Answer

The vegetarian athletes (some athletes) must avoid red meat, making 'some athletes avoid red meat' necessarily true.

Question 3

If a syllogism has a true conclusion, it must be valid. Which statement best identifies the flaw in this claim?

Accepted Answer

A true conclusion can result from an invalid argument

Answer

An invalid argument can accidentally produce a true conclusion; validity concerns the argument's structure, not the conclusion's truth value.

Question 4

No one who cheats on exams graduates with honors. Taylor graduated with honors. What follows?

Accepted Answer

Taylor did not cheat on exams

Answer

Modus tollens: honors graduation is incompatible with cheating, so an honors graduate cannot be a cheater.

Question 5

All X are Y. No Y are Z. Which conclusion follows with certainty?

Accepted Answer

No X are Z

Answer

X is a subset of Y, and Y excludes Z entirely; therefore X, being within Y, must also exclude Z.

(CCTST) California Critical Thinking Skills Test Practice Test