I have say 100 different schools. In this data, for each school, I have a sample number of students who pass an exam and the percentage of students who pass an exam. This is given for 2 years. Would the true population be calculated using confidence interval wrt to sample size of each school or a single sample size which is the sum total of number of samples in all 100 schools? This is for comparing school performance using hypothesis testing and I cant figure this particular part out.

Description:
In each school, students are sampled(not equally in each school), and the pass percentage is calculated. Now the null hypothesis is that the true pass rate of school 1 and school 2 are equal. The alternate hypothesis is that the pass rate at school 1 is higher than school 2. Using only the sample size of each school and the sample pass rate, is it possible to reject the null hypothesis? How will the true pass rate be calculated? wrt to the school itself or all the school, since factors such as location, student family background etc may be influencing factors which are different in each school.