The theoretical probability is given by 1 over the number of hobbies.
If there is a total of 8 hobbies, the probability of a student having a specific hobby is:
[tex]P=\frac{1}{8}[/tex]The experimental probability is given by the number of students with that hobby over the total number of students. If 3 students have the hobby roller skating among the 24 students surveyed, the probability is:
[tex]P=\frac{3}{24}=\frac{1}{8}[/tex]