The arithmetic mean is a single value meant to "sum up" a data set.
Letís say you have this data set:
1, 1, 2, 2, 2, 3, 3, 4, 5, 5
What single value best represents this data?
To calculate the mean, first add up all values, then divide by the total number of values you have.
There are two types of arithmetic mean: population mean, and sample mean. They're both calculated the same way, but they're written differently:
Remember that N represents the size of a population, and n represents the size of a sample.