A computer generates 75 integers from 1 to 8 at random. The results are recorded in this table.
What is the experimental probability of the computer generating a 3 or a 4?

Outcome-1-2-3-4-5-6-7-8
Number of times outcome occurred-12-16-9-12-4-7-5-10
O 9%
O 15%
O 21%
O 28%