According to the probability distribution, there is a 0% probability that a randomly selected student earns more than 18 credits.
Thus, the probability distribution for the number of credits earned is:
[tex]P(X = 3) = 0.06[/tex]
[tex]P(X = 6) = 0.06[/tex]
[tex]P(X = 9) = 0.12[/tex]
[tex]P(X = 12) = 0.2[/tex]
[tex]P(X = 15) = 0.41[/tex]
[tex]P(X = 18) = 0.15[/tex]
Since no person takes more than 6 courses, there is a 0% probability that a randomly selected student earns more than 18 credits.
A similar problem is given at https://brainly.com/question/25117113