Given the following information, what is the standard deviation for this stock? (Hint: you'll need to find the expected return first)

Probabilities:

Recession: 0.3

Normal: 0.55

Boom: 0.15

Returns:

Recession: -11%

Normal: 9%

Boom: 13%

a) 11.19%

b) 10.47%

c) 12.05%

d) 9.66%

e) 8.39%

Is there a way to find this using TI84 - plus as well?