First question with answer was: A stock has a 10% chance of losing 5%, a 20% chance of making a10%, a 30% chance of making 20% and a 40% chance of making 40%. The expected return on this stock is .235

second question (the one i need help with ) A stock has a 20% probability of losing 10% next year, a 30% chance of earning 6%, a 30% chance of earning 16% and a 20% chance of earning 42%. Given that probability distribution for the stock what is the stocks standard deviation? This is the same stock as in question 1.