Diagrams and validity

Exercise and reference answers

Questions

1. Question

   To disprove a conclusion you need

   Choices

   1. every diagram to fail
   2. one consistent diagram where it fails
   3. no diagram at all

   Correct choice

   one consistent diagram where it fails

2. Question

   To accept a conclusion you need

   Choices

   1. one diagram to support it
   2. two diagrams
   3. every consistent diagram to support it

   Correct choice

   every consistent diagram to support it

3. Question

   A circle in a logic diagram stands for

   Choices

   1. a class
   2. a number
   3. a person

   Correct choice

   a class

Explanation