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 1 2 3 4 5
P(X=x)
0.05 0.25 0.36 0.15 0.13 0.06
(a) Compute the mean, or expected value, of the random
variable X
(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.)