To arrive at your stat maximums, the system adds up the numbers below for each skill in your primary and secondary slots. Primary skills count twice; no other skills count at all. The totals are then divided by 9 (3 primes x 2 = 6, plus 3 secondaries = 9) to arrive at your stat caps.
You may use the stat calculator to find out what your maximum stats would be, if you were to choose the skills in question.