Syllogisms and Venn Diagrams: All, Some, No
Draw each All, Some and No statement as circles, cancel the middle term, and accept a conclusion only if no drawing of the premises can make it false.
What it is
A syllogism is a short argument: two statements called premises, then a conclusion that is supposed to follow from them.
All cashiers are bonded. Nilo is a cashier. So Nilo is bonded.
The premises use three words: All, Some and No. A Venn diagram draws each group as a circle, so you can see what the premises really say, and what they do not say.
Why it matters on the exam
Logic items in the Analytical Ability part of the Professional exam ask you to pick the valid conclusion, or to judge which of several inferences (I, II, III) must be true. The wrong choices are built from a few common slips: reversing an "All" statement, turning "some" into "all", and linking two groups only because they share a trait. Even published answer keys make these slips. A circle drawing protects you.
At work, the same thinking stops you from drawing a conclusion a memo or a rule does not support.
Which conclusion follows?
- Everyone who passed a road test is a licensed driver.
- Mylene has passed a road test.
- Mylene is the best driver in the province.
- Some people who passed a road test are not licensed drivers.
The rest of this lesson, and every other lesson, is part of ReviewTayo.
Read moreIn the full lesson
- How to recognize it on the test
- What to look for (5 checks)
- All 8 rules and tools
- 4 worked examples, every step explained
- 6 common mistakes and how to fix them
- 3 exam techniques
- Remember: 5 key points
- Practice questions with explanations, and your progress saved
More Analytical Ability lessons
ReviewTayo has 51 lessons that follow the official scope of the exam, each with rules, worked examples, common mistakes and practice. Open one and read the first part.