The amount of baked ziti per person depends on a few factors, such as how hungry each person is, the size of the portions, and what else is served with it.  Generally speaking, a half-cup to one cup of cooked ziti per person should be adequate. If the ziti dish is an entree in its own right, a larger portion may be necessary.  Additionally, if the ziti is served as a side to a larger dish or alongside other sides, then smaller portions might be more appropriate.  Keep in mind that all food servings should remain proportional to ensure balanced nutrition and satisfaction for all guests.