Space Shuttles. The National Aeronautics and Space Administration (NASA) compiles data on space-shuttle launches and publishes them on its website. The following table displays a frequency distribution for the number of crew members on each shuttle mission from April 12, 1981 to July 8, 2011.

Crew size 24 5 6 7 8 Frequency 4 3 36 28 63 1 Let X denote the crew size of a randomly selected shuttle mission between the aforementioned dates.

a. What are the possible values of the random variable X?

b. Use random-variable notation to represent the event that the shuttle mission obtained has a crew size of 7.

c. Find P(X = 4); interpret in terms of percentages.

d. Obtain the probability distribution of X.

e. Construct a probability histogram for X.