Waiting in line - Wendy's manager performed a study to determine a probability distribution for the number of people, X, waiting in line during lunch. The results were as follows:

x P(x) x P(x)

0 0.011 7 0.098

1 0.035 8 0.063

2 0.089 9 0.035

3 0.150 10 0.019

4 0.186 11 0.004

5 0.172 12 0.006

6 0.132

a. Calculate the standard deviation of the random variable X (to one decimal value)

b What is the probability that 8 people are waiting in line for lunch?

c. What is the probability that 10 or more people are waiting?