What do probabilities of 0 and 1 mean?
PICTURE THIS: 1, 2, 2, 8
Simple meaning
A probability of 0 means the event is treated as impossible under the model, and 1 means it is treated as certain.
WHY — Probability instead of guessing?
Why interviewers care about Probability:
who only read docs from people who shipped.
and tied to Data Science work.
Name the idea, why it exists, then one short example.
End with when you use it and one common pitfall.
STEPS — What happens step by step?
Before you speak the answer, walk the interviewer through these steps:
- 1A probability of 0
means the event is treated as impossible under the model, and 1 means it is treated as certain.
- 2In real data work
those extremes are rare because models are approximate and rare events still occur.
- 3Interviewers want you to
treat 0 and 1 as model statements, not as proof about the physical world.
- 4Give an example
One tiny concrete case you can say aloud.
- 5Common mistake
What juniors usually get wrong.
- 6Close
When you pick this over the alternative.
EXAMPLE — See it in action
Here's a short line you can speak, broken into clear beats:
Note: Adapt this scaffold to your own project — keep it under 60–90 seconds.
Key takeaway
A probability of 0 means the event is treated as impossible under the model, and 1 means it is treated as certain. In real data work those extremes are rare because models are approximate and rare events still occur.