Mean | Statistics

The mean is the average value of a sample or a population. The mean is calculated as the sum of all values in a population or a sample divided by the number of observations in a population or a sample.

There is a difference between the mean of a population and the mean of a sample. An average value calculated from a population is the real mean and you call values calculated from the entire population as parameters. An average value calculated from a sample is an estimate of the mean of a population.

Mean: The sum of all values / number of observations

If we have three observations of 5, 10 and 15, then the mean is 10 (30/3).

When the population is small, one can calculate the mean of the population directly, most often, however, the population is large, so we have to calculate an estimate of the population mean from a sample. In order to calculate the average, the data level must be interval data or ratio data.

Properties for the mean:
1. All data that is interval data or ratio data has a mean value.
2. All values are included when we are calculating the mean.
3. A data set has only one average value, the average value is unique.
4. The mean can be used to compare multiple populations.
5. The sum of all deviations from the mean is always 0.