What is sampling bias?
PICTURE THIS: OVERFITTING
Simple meaning
Sampling bias happens when some members of the population are systematically more likely to appear than others.
WHY — Sampling instead of guessing?
Why interviewers care about Sampling:
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:
- 1Sampling bias happens when
some members of the population are systematically more likely to appear than others.
- 2Online surveys that only
reach desktop power users undercount mobile-only customers.
- 3No amount of fancy
modeling fully repairs a sample that never saw the missing group.
- 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
Sampling bias happens when some members of the population are systematically more likely to appear than others. Online surveys that only reach desktop power users undercount mobile-only customers.