Returns earned over a given time period are called realized returns. Historical data on realized returns is often used to estimate future results. Analysts across companies use realized stock returns to estimate the risk of a stock.

Consider the case of Happy Dog Soap Inc. (HDS):

Five years of realized returns for HDS are given in the following table. Remember:

1.	While HDS was started 40 years ago, its common stock has been publicly traded for the past 25 years.
2.	The returns on its equity are calculated as arithmetic returns.
3.	The historical returns for HDS for 2012 to 2016 are:

	2012	2013	2014	2015	2016
Stock return	16.25%	11.05%	19.50%	27.30%	8.45%

Given the preceding data, the average realized return on HDSs stock is (33.02%, 16.51%, 41.28%, 51.18%)

The preceding data series represents (the universerve, a sample, the population) of HDSs historical returns. Based on this conclusion, the standard deviation of HDSs historical returns is (10.02%, 5.71%, 6.64%, 7.42%) .

If investors expect the average realized return from 2012 to 2016 on HDSs stock to continue into the future, its coefficient of variation (CV) will be (0.45, 0.83, 0.38, 0.52) .