Glossary
median
The median is the middle value of a set of numbers once they are in order. Half the values lie below it, half above, and it is not moved much by an outlier.
The median is the middle value of a set of numbers after the set has been put in order. In 3, 7, 8, 10, 14 the median is 8: two values sit below it and two above. Sorting first is not optional — the numbers in a question are not handed to you in order, and forgetting to sort them is the standard error.
An even count has no single middle value, so the median is the average of the two middle values: in 4, 9, 11, 20 the median is 10, which is the average of 9 and 11. Note that the median of that set is a number that does not appear in the set at all, which is perfectly normal.
Why the ASVAB asks about it alongside the mean: an outlier moves one and not the other. In 3, 7, 8, 10, 60 the average jumps from 8.8 to 17.6, while the median stays at 8. That resistance is why incomes and house prices are usually reported as medians, and it is the comparison a statistics question is usually testing.
Taught in
Related terms
- mode — The mode is the value that appears most often in a set of numbers. A set may have one mode, several modes, or no mode if every value appears once.
- range — The range of a data set is the difference between its largest and smallest values — subtract the smallest from the largest. It is a measure of spread, not of center.
Source: Official ASVAB — subtest descriptions (what each subtest asks) and the CAT-ASVAB scored-question counts (accessed 2026-09)