CRMcNeill Director of Engineering
Joined: 05 Apr 2010 Posts: 10403 Location: Redding System, California Sector, on the I5 Hyperspace Route.

Posted: Mon Aug 29, 2016 12:54 am Post subject: Guidelines for Generating a 2D Results Tables 


The probability of a particular number coming up on a roll of 2D changes from number to number, with the numerical odds as follows:2 = 1/36
3 = 2/36
4 = 3/36
5 = 4/36
6 = 5/36
7 = 6/36
8 = 5/36
9 = 4/36
10 = 3/36
11 = 2/36
12 = 1/36
So, for example, whenever you roll 2D, the statistically most likely result is a 7 (a 6in36 chance, or 1in6) while the statistically least likely result is either a 2 or a 12 (each with a 1in36 chance).
When generating a list, you can play with the numbers, so as to make a given result more likely. For example, if you wanted to have two results of equal likelihood on a 2D roll, you would assign one to the 23 result, and the other to 4, giving both a statistical likelihood of 3/36 by adding the odds of a given set of numbers together to create a greater likelihood than either would generate on their own (3/36 = 1/36 + 2/36).
For example, on a 2D Table I posted earlier, I used the following:
2 = 1/36
3 = 2/36
45 = 7/36 (3/36 + 4/36)
69 = 20/36 (5/36 + 6/36 + 5/36 + 4/36)
1011 = 5/36 (3/36 + 2/36)
12 = 1/36
Essentially, by treating the probability numbers as fractions, adding the numerators of a multinumber set will give you an idea how likely a given result is, and help you structure your lists to make a particular result the most likely outcome.
Enjoy. _________________ "No set of rules can cover every situation. It's expected that you will make up new rules to suit the needs of your game."  The Star Wars Roleplaying Game, 2R&E, pg. 69, WEG, 1996.

