Assume that an investment is forecast to produce the following returns:

a 20% probability of a 12% return;

a 50% probability of a 16% return;

a 30.000% probability of a 22% return.

What is the standard deviation of returns for this investment, to the nearest 0.01%? Drop the % symbol. E.g., if your answer is 3.105%, record it as 3.11.