There's only 15 possible outcomes and all you'd be doing is measuring the randomness of Excel's random number generator, which should result in an even distribution. Or am I missing something? I managed to miss statistics in school.

In any case, how about putting your constants at the top of your sheet, make one row of formulas based on a single random value, and copying that down for 1000 rows? Then do your stats and charts on that table's data.