I need to find the correct formula in statistics - probability I believe - to get an answer to this question:

The graduation rate of foreign students in a military training class is low. To select better students and hopefully improve the graduation rate, we want to find which combination of personal characteristics in students has the best probability of graduating.

For example, ages 21 - 30, 31-40, etc.

Married or unmarried

Literacy rate

Rank

Education level

I do not need to solve the problem with known data. I need to demonstrate the correct formula and procedure to use to look for the answer.