Please answer A and B

A commuter must pass through 5 traffic lights on her way to work and will have to stop at each one that is red. She estimates the probability model for the number of red lights she hits, as shown below. X =# of red 0 2 3 4 5 P(X = x) |0.05 0.24 0.34 0.15 0.13 0.09 (a) Compute the mean, or expected value, of the random variable X. H= (Round to one decimal place as needed.) (b) Compute the standard deviation of the random variable X. (Round the final answer to one decimal place as needed. Round all intermediate values to three decimal places as needed.)