In 2010, Cal State San Bernardino accepted just a quarter of all applicants, but this had more to do with a high number of applicants than high admissions standards. In the graph above, the green and blue dots represent students who got in. As you can see, most students who were accepted by this member of California State University System had grades in the "B-" range or higher, SAT scores (CR+M+W) of 1250 or higher, and ACT scores of 16 or higher. However, note that there are some red and yellow data points (rejected and waitlisted students) scattered throughout the graph. Some students with grades and test scores that seem to be on target for CSUSB did not get in.
Unlike the University of California System, the California State University admission process is not holistic. Except for EOP students, applicants do not need to submit letters of recommendation or an application essay, and extracurricular involvement is not part of the standard application. Thus, the reason why an applicant with adequate scores and grades would be rejected tends to come down to a couple factors such as insufficient college preparatory classes or an incomplete application.
To learn more about the California State University at San Bernardino, high school GPAs, SAT scores and ACT scores, these articles can help: