The following table gives the flight times in minutes for Southwest Airlines flights from Dallas to Houston during the first five days of August 2010.

a. Complete the third column of the table by computing the probability of each flight time. Round your answers to three decimal places.

Flight Time (min) # Flights Probability
50 1
51 1
52 4
53 7
54 11
55 17
56 19
57 13
58 11
59 14
60 6
61 5
62 5
63 4
64 3
65 1
66 1
67 0
68 1

b. If one flight is selected at random, what is the probability that its flying time is 55 minutes or less?

c. Using the data from part a, what is the expected value of the flight times during this period. Round your answer to three decimal places.