About average calculator
The average summarises a list of numbers with one value. The mean, median and mode answer slightly different questions.
The three averages
- Mean: add everything and divide by how many numbers there are.
- Median: the middle value when the numbers are sorted. It ignores extreme values.
- Mode: the value that appears most often.
Which to use
For incomes or house prices, the median is better because a few very large values pull the mean up. The mean suits evenly spread data such as test scores.
A worked example
Test scores of 72, 85, 90, 85 and 68 add up to 400, so the mean is 80. Sorted, they are 68, 72, 85, 85, 90, so the median is 85. The mode, the most frequent value, is also 85.
Weighted averages
When items count unequally, such as coursework worth 40 percent and an exam worth 60, multiply each by its weight before adding. A plain mean would give the wrong answer.
