Developing math vocabulary
Median
Pronunciation: MEE-dee-un
The median is the middle value of an ordered data set, or the mean of the two middle values when the count is even.
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Plain language
What it means
The median is the middle value of an ordered data set, or the mean of the two middle values when the count is even.
Formal meaning
Mathematical definition
The median is the 50th percentile and divides ordered observations into lower and upper halves.
Where it fits
Its place in mathematics
Median provides a center measure that is resistant to unusually large or small observations.
Why it matters
The practical reason to learn it
It often represents skewed data, such as income or home prices, more faithfully than the mean.
Worked example
Find a median
Find the median of 9, 2, 12, 5, and 7.
- Order the values: 2, 5, 7, 9, 12.
- Choose the middle value.
The median is 7.
Real-life example
Where this appears
A real-estate analyst may report a median sale price because a few luxury sales can distort the mean.
Common mistake
What to watch for
Selecting the middle value before sorting the data.
Memory tip
Keep this in mind
Always sort first and count how many observations there are.
Little-known fact
Keep curiosity alive
The median can stay unchanged even when an extreme observation becomes much larger.
A profession that uses this idea
Median prices resist extremes
Businesses use medians when a few unusually high or low values would distort an average.
Explore Merchants & Business OwnersFollow the learning trail
Prerequisites, related ideas and next concepts
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