of this security. In our case, it’s

Second, you need to subtract each year’s growth from this average and then square those numbers:

annual growth

Third, you need to find the sum of all the squared differences:

average annual growth

and divide this by the number of years the investment was held -1, which in the current case is 5 – 1 = 4, so

average annual growth

The last step is to find the square root of this number, which is

Standard deviation