Please show work using formulas.

7. Given the following probability distribution for Northern Inc. (NOI), answer the following questions: State of EconomyProbability Boom Slight Boom Average Recession NOI returns 20% 10% 50% 20% 25% 1 5% 8% -14% a) (12 points) What are the expected return and standard deviation for NOI? b) (3 points) If this were a continuous distribution, approximately 95.44% of the time, the return for NOI would fall between and