Engineering Economy 7th Edition by Leland Blank ,Anthony Tarquin

Exercise 15

A discrete variable X can take on integer values of 1 to 10. A sample of size 50 results in the following probability estimates:
a) Write out and graph the cumulative distribution.
b) Calculate the following probabilities using the cumulative distribution: X is between 6 and 10, and X has the values 4, 5, or 6.
c) Use the cumulative distribution to show that P ( X = 7 or 8) = 0.0. Even though this probability is zero, the statement about X is that it can take on integer values of 1 to 10. How do you explain the apparent contradiction in these two statements