What are the odds?
Unearthed Arcana's Method V analyzed
by Arthur J. Hedge III
 
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Dragon #117 - 1st Edition AD&D - Dragon magazine

With the introduction of Unearthed
Arcana, AD&D® game players were presented
with a new way to generate player
characters. One now selects the class of
the character first and then rolls a number
of six-sided dice for each ability, as
indicated by the chart accompanying
Method V on page 74. The probability of
rolling a given number is no longer given
by a standard bell curve and is not simple
to calculate. The DM needs to
have a better idea of what he is giving the
players by allowing this system to be used.
This article presents a set of tables listing
the various probabilities involved with this
new method of character generation.

A new notation is given here for rolling
a group of dice. When a number between
3 and 18 is generated using nine six-sided
dice, I suggest using the notation ?9d6s3?
instead of ?9d6.? The first digit represents
the number of dice to be rolled, the second
digit represents the type of die to be
used, and the third digit represents the
number of dice to be added together by
selecting the highest rolled numbers. In
the tables given here, the "Total" figure
refers to the number of different possible
rolls; the ?Times? column refers to the
number of times that particular number is
generated; and, the ?Probability? column
refers to the probability of generating that
particular number, given that a 100%
chance equals a probability figure of 1.

These tables were generated on a DEC
VAX computer system using a program
written in C. Good luck rolling those 18s!

Table 1: 3d6s3 (Total 216)
Number Times Probability
3 1 0.00462963
4 3 0.01388889
5 6 0.02777778
6 10 0.04629629
7 15 0.06944445
8 21 0.09722222
9 25 0.11574074
10 27 0.12500000
11 27 0.12500000
12 25 0.11574074
13 21 0.09722222
14 15 0.06944445
15 10 0.04629629
16 6 0.02777778
17 3 0.01388889
18 1 0.00462963

Table 2: 4d6s3 (Total 1,296)
Number Times Probability
3 1 0.00077160
4 4 0.00308642
5 10 0.00771605
6 21 0.01620370
7 38 0.02932099
8 62 0.04783951
9 91 0.07021605
10 122 0.09413581
11 148 0.11419753
12 167 0.12885803
13 172 0.13271604
14 160 0.12345679
15 131 0.10108025
16 94 0.07253087
17 54 0.04166667
18 21 0.01620370

Table 3: 5d6s3 (Total 7,776)
Number Times Probability
3 1 0.00012860
4 5 0.00064300
5 15 0.00192901
6 41 0.00527623
7 90 0.01157407
8 170 0.02186214
9 296 0.03806584
10 470 0.06044239
11 665 0.08551954
12 881 0.11329733
13 1055 0.13567387
14 1155 0.14853396
15 1111 0.14287551
16 935 0.12024177
17 610 0.07844650
18 276 0.03549383

Table 4: 6d6s3 (Total 46,656)
Number Times Probability
3 1 0.00002143
4 6 0.00012860
5 21 0.00045010
6 78 0.00167181
7 207 0.00443673
8 447 0.00958076
9 914 0.01959019
10 1677 0.03594393
11 2706 0.05799897
12 4135 0.08862750
13 5646 0.12101337
14 7056 0.15123457
15 7770 0.16653806
16 7551 0.16184413
17 5535 0.11863426
18 2906 0.06228567

Table 5: 7d6s3 (Total 279,936)
Number Times Probability
3 1 0.00000357
4 7 0.00002501
5 28 0.00010002
6 148 0.00052869
7 469 0.00167538
8 1141 0.00407593
9 2745 0.00980581
10 5747 0.02052969
11 10409 0.03718350
12 18159 0.06486840
13 27979 0.09994785
14 39277 0.14030707
15 48798 0.17431842
16 54096 0.19324417
17 44121 0.15761103
18 26811 0.09577546

Table 6: 8d6s3 (Total 1,679,616)
Number Times Probability
3 1 0.00000060
4 8 0.00000476
5 36 0.00002143
6 283 0.00016849
7 1052 0.00062633
8 2844 0.00169324
9 8117 0.00483265
10 19252 0.01146214
11 38648 0.02301002
12 76543 0.04557173
13 132168 0.07868941
14 206032 0.12266614
15 286501 0.17057529
16 358828 0.21363692
17 322812 0.19219393
18 226491 0.13484690

Table 7: 9d6s3 (Total 10,077,696)
Number Times Probability
3 1 0.00000010
4 9 0.00000089
5 45 0.00000447
6 547 0.00005428
7 2340 0.00023220
8 6948 0.00068944
9 23806 0.00236225
10 63612 0.00631216
11 140049 0.01389693
12 314245 0.03118223
13 604863 0.06001997
14 1037223 0.10292263
15 1607641 0.15952466
16 2257245 0.22398423
17 2222676 0.22055398
18 1796446 0.17825960