Please solve the problem. Show your complete solution and the formula that you use. Thank you so much! (Identify all what is needed in the problem)

2. Suppose you are a player of League of Legends. Let X be the number of kills you get in a match whose probability mass function is given below: 2 3 4 5 6 8 P(X = x) 0.04 0.06 0.08 0.09 0.11 0.18 0.21 0.13 0.10 Calculate the expected value, variance, and standard deviation of the given discrete random variable