Mean
Average value.
What does Mean mean?
The mean, commonly known as the average, is the sum of all values in a data set divided by the number of values. It is one of the most widely used measures of central tendency in statistics, providing a single number that represents the typical value in a distribution. The mean is useful for summarizing data, comparing groups, and detecting trends.
How to calculate Mean
To calculate the mean, add all the values together and divide by the count of values. The formula is: Mean = Sum / Count. For example, given the values 10, 20, 30, 40, and 50, the sum is 150 and the count is 5, so the mean is 150 / 5 = 30. This calculator also shows the total count, sum, minimum, and maximum of your data set.
FAQ
The mean is the arithmetic average of all values. The median is the middle value when data is sorted. The mode is the most frequently occurring value. Each measure of central tendency provides different insight: the mean accounts for every value, the median resists outliers, and the mode identifies the most common value.
Use the mean when your data is roughly symmetric and has no extreme outliers. Use the median when your data is skewed or contains outliers, because the median is not affected by extremely high or low values. For example, median income is often more representative than mean income because a few very high earners can inflate the average.
Yes. The mean is sensitive to outliers — a single extremely large or small value can pull the average significantly in one direction. For instance, in the set {1, 2, 3, 4, 100}, the mean is 22, which does not represent most of the values well. In such cases, the median (3) gives a better picture of the typical value.
The most common type is the arithmetic mean (sum divided by count), which is what this calculator computes. Other types include the geometric mean (used for growth rates and ratios), the harmonic mean (used for rates and speeds), and the weighted mean (where each value has a different importance).
You need at least one value to calculate a mean. However, the mean becomes more statistically meaningful with larger sample sizes. With very few data points, the mean may not be representative of the underlying population.
Related calculators
- Median— Middle value.
- Mode— Most frequent value.
- Standard Deviation— Spread of values.
- Variance— Squared dispersion measure.