Mean Calculator

Calculate the arithmetic mean (average) of a list of numbers with sum, count, minimum, and maximum.

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18

Mean

108

Sum

6

Count

Mean18
Sum108
Count6
Minimum4
Maximum42

Also in Statistics

Descriptive Statistics

Mean calculator — arithmetic average with sum and count

The arithmetic mean (average) is the most widely used measure of central tendency. It is the sum of all values divided by the count of values. The mean is the balance point of a distribution — the value at which the total positive deviations equal the total negative deviations.

Calculating the mean

Mean = (x₁ + x₂ + … + xₙ) / n. Add all values and divide by how many there are. For [4, 8, 15, 16, 23, 42], the sum is 108 and the count is 6, so the mean is 108 / 6 = 18.

The mean is sensitive to every value in the dataset. Adding one very large or very small value pulls the mean significantly. This is why the mean is sometimes called a non-robust statistic. For skewed distributions or data with outliers, the median is often a better measure of the "typical" value.

Mean vs. median vs. mode

In a perfectly symmetric distribution, the mean, median, and mode are equal. In a right-skewed distribution (long tail on the right), the mean is pulled upward above the median. In a left-skewed distribution, the mean falls below the median. This is why income data is usually summarised by the median (the middle earner) rather than the mean (inflated by a few very high earners).

The mode is the most common value. For a dataset with one clear peak, mode ≤ median ≤ mean holds for right-skewed data. All three together tell a much richer story than any single statistic alone.

Population mean vs. sample mean

The population mean (μ) is the mean of every member of the group you are studying. The sample mean (x̄) is the mean of a subset. Both are calculated the same way (sum divided by count), but they have different notations and different implications: the sample mean is an estimate of the population mean, subject to sampling error.

Frequently asked questions

When should I use the mean vs. median?

Use the mean when your data is roughly symmetric and has no extreme outliers — it uses all the information in the data. Use the median when the data is skewed, has outliers, or is ordinal. Income, house prices, and response times are commonly reported as medians because a few very large values would make the mean misleadingly high.

Can the mean be outside the range of the data?

No. The mean is always between the minimum and maximum values of the dataset. It is a weighted balance point, so it must lie within the range.

How is the weighted mean different?

The ordinary arithmetic mean treats all values equally. A weighted mean multiplies each value by a weight before summing, then divides by the total weight. Course grade averages with different credit-hour weights are a common example: Weighted mean = Σ(value × weight) / Σweight.

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