What is the median of 5, 7, 9, 11, 15?

9

The median is the middle value when the data is arranged in order. For 5, 7, 9, 11, 15, the middle value is 9.

Understanding Statistics questions

Statistics questions ask you to summarise a data set with a single representative figure or a measure of spread. The arithmetic is light; picking the right measure is the real skill.

How to approach it

1. Order the data when median or range is involved.
2. Use mean = sum ÷ number of values, median = middle value, mode = most frequent value.
3. For grouped data, use class midpoints as representative values.
4. State the answer with the same units as the original data.

Common mistakes to avoid

• Forgetting to sort the values before finding the median.
• Including the frequency column in the sum instead of the values.
• Assuming a data set has exactly one mode.

Where it appears: Covered in CBSE Class 9–12, IGCSE, and IB Applications and Interpretation.