Mean Formula
Every data value contributes equally. That is why a single outlier can move the mean a long way.
Variables
- xᵢ — The i-th observation
- n — How many observations
When to use it
Summarizing roughly symmetric numerical data.
Worked example
2, 4, 6, 8
- 20/4 = 5
Answer: 5
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Example problems
Common mistakes
Averaging averages
Combine groups with a weighted mean using group sizes.
Related calculators
Frequently asked questions
Population vs sample notation?
μ often denotes a population mean; x̄ denotes a sample mean. The arithmetic is the same if you have every value listed.