Answer: The complement 'none' is a single scenario, while 'at least one' splits into many separate cases.
- A The complement always produces a larger and therefore safer probability value
- B The complement 'none' is a single scenario, while 'at least one' splits into many separate cases
- C The complement rule is the only exact method available for such events
- D 'At least one' events are always impossible to count directly in principle
Correct answer: B. The complement 'none' is a single scenario, while 'at least one' splits into many separate cases
Explanation: Counting 'exactly one', 'exactly two' and so on is laborious, whereas 'none' is a single case, so 1 − P(none) is far quicker and less error-prone.
Concept context
Random experiments, sample space, events, and the axiomatic approach to probability