A stocks returns have the following distribution:

Probability Stock Return:

0.3 11%

0.4 15%

0.3 45%

The stocks expected return is 16.2%. Calculate its standard deviation.

a.56%

b.28%

c.19.13%

d.21.71%

e.22.88%

*I can use a Graphing calculator for this question! Please include steps to solve (on calc if possible!) Thank you! :)