Please get familiar with your class rosters so that you know roughly how many freshmen, sophomores, juniors and seniors. If you teach MM!PPC (Pre-cal), you should not have any seniors in your class. If you teach MG21, your best students are probably freshmen or sophomores. And if you teach MR21, your best students should be sophomores and your weakest students are probably seniors. In other words, the more freshmen you have in MG21 and more sophomores you have in MR21, the higher the passing percentage should be. Please make sure you also know how many students have an IEP in your classes and who are entitled to extra time and separate locations for taking exams. You should also follow the recommendations in the IEP.
Imagine, the best students, the ones you should expect the most from can be determined by their year in school. If you have seniors in your trig class, don't expect much from them. It is not probable that a child who has not advanced to be bright. But, if your stats are bad, don't use any of the above as an excuse. Just call the parent and maybe they can change the child's birth date to make them younger and smarter.