A single test's difficulty may be relative to the test taker. It can however be objectively compared to the difficulty of other standardized tests. Compared to other standardized tests, it's clearly designed for a person of average intelligence to do well. Even a person of below average intelligence shouldn't struggle to score at least 35, which was the absolute minimum score allowed.

The purpose of the test is not as focused on determining *if* a person is eligible for service, but rather for what jobs they're best suited *when* they enter. Of course if there are no vacancies in the jobs an applicant is qualified for, they'll be wait-listed. I had to wait almost a year for the job I wanted. 

Then there was the Force Shaping period. They were so busy getting people out, I'm sure that practically nobody was getting in. I entered right before that, and a lot of the first termers I served with volunteered for Force Shaping within months.