You are a portfolio manager

You are a portfolio manager. John Smith, one of your clients, by providing you the following formation requested you to calculate standard deviation of Shah Corporation stock and High Fly Corporation.  

Shah Corporation Stock

State of Economy        Probability of State of Economy     Rate of Returns if State Occurs

Boom                                          5%                                            13%

Good                                          25%                                            8%

poor                                            50%                                            2%

Bust                                            20%                                            -6%

High Fly Corporation Stock

State of Economy        Probability of State of Economy     Rate of Returns if State Occurs

Boom                                          5%                                            40%

Good                                          25%                                           25%

poor                                            50%                                           -5%

Bust                                            20%                                           -28%

Based on the given information, what is the standard deviation of the returns on i) Shah Corporation and ii) High Fly Corporation? Which stock has higher standard deviation? Why? Please provide your reasoning. Please show all the calculations by which you came up with the final answer.