What is the Median?
The middle number in a ranked set of data
In math, the median of a data set is the value that falls in the middle of a data set when the numbers are arranged in order from least to greatest. If the set has an odd number of values, the median is the middle number. If there’s an even number of values, the median is the average of the two middle numbers.
For example:
- In the set {2, 5, 7}, the median is 5.
- In the set {4, 6, 8, 10}, the median is (6 + 8) ÷ 2 = 7.
The median is useful because it gives a good sense of the "center" of the data, especially when there are very high or very low values (called outliers) that might distort the average.
We use medians to:
- Summarize and interpret data sets
- Understand typical values in surveys or studies
- Make decisions based on real-world data
When Do Students Learn About Medians?
Students begin learning about medians as part of their introduction to data analysis in upper elementary school.
Grades 4–5 – Introduction to the Median
Students arrange data sets in order and identify the median value. They learn how medians can represent the center of a group of numbers.
Grades 6+ – Applying the Median in Data Analysis
Students use medians in larger data sets and explore how it compares with other measures of center like the mean and mode.
