What is the interquartile range, and when is it useful?
PICTURE THIS: HOW TO EXPLAIN IT
Simple meaning
The IQR is the 75th percentile minus the 25th percentile, the spread of the middle half of the data.
WHY — Statistics instead of guessing?
Why interviewers care about Statistics:
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:
- 1The IQR is the
75th percentile minus the 25th percentile, the spread of the middle half of the data.
- 2It is robust to
extreme tails compared with standard deviation.
- 3IQR is the backbone
of the common box-plot outlier rule and of robust scale estimates.
- 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
The IQR is the 75th percentile minus the 25th percentile, the spread of the middle half of the data. It is robust to extreme tails compared with standard deviation.