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)	0.06	0.24	0.35	0.15	0.15	0.05

(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.)

Your company bids for two contracts. You believe the probability that you get contract #1 is 0.4.

If you get contract #1, the probability you also get contract #2 will be 0.2, and if you do not get contract #1, the probability that you get contract #2 will be 0.1.

a) Let X be the number of contracts you get. Find the probability model for X. (Type integers or decimals. Do not round.)

x	0	1	2
P(x)	enter your response here	enter your response here	enter your response here

A certain tennis player makes a successful first serve 72% of the time. Suppose the tennis player serves 70 times in a match. . c) What's the probability she makes at least 57 first serves

(Use the answers from part a to find this answer. Round to four decimal places as needed.)

EX= 50.4

SD(X)= 3.76