The average of all the data in a set is the mean. i.e., the sum of all data in a set divided by the total number of items. In this online mean calculator, you can calculate the average (mean) for the values you enter.
For a set of data : 3,12, 27,13,5
Mean = 3+12+27+13+5 / 5
Mean = 60 / 5
Mean = 12
Mean is sometimes considered as an economic measure.