You may use “average” to measure or show the size/length of data group.
For example, if you simply show the monthly sales revenue, most people use daily “average”.
However, it only shows one-sided nature of the data.
You also have to look at the dispersion of each single data as “average” hides this important nature of the original data.
“Data Dispersion” implies , in the business world, risk of the business (such as revenue, profit etc.) or accuracy of production etc.
The most common index of data dispersion may be “standard deviation”.
These two axes complement each other and indispensable to show the nature of the data properly.