Answer:
12.4
Explanation:
We need to,first of all, determine the arithmetic average return of all the returns, which is the sum of the returns divided by the number of returns
average return=(6%+3%+18%+3%)/4
average return=7.50%
Years return (return-average return) (return-average return)^2
1 6.00% -1.50% 0.022500%
2 3.00% -4.50% 0.202500%
3 18.00% 10.50% 1.102500%
4 3.00% -4.50% 0.202500%
average return 7.50% variance 1.530000%
standard deviation=variance^(1/2) 12.4%