# pair o' dice no paradox, men *The Urth list — 1 messages, 1 voices, 15 Dec 2001* > Exported from an unofficial mirror of a public mailing list. Copyright > in each message remains with the person who wrote it. > Email addresses are obscured as `user at host`, the form the original > archive published. This file was rebuilt from parsed fields rather than > retained headers, so it is faithful in content but not byte-exact. --- ### Michael Andre-Driussi *15 Dec 2001, 15:43* Thanks Sunanda! Joel Sieh also caught this and I thought he and I had posted to the list! Here is my quote and response to him. >> Joel Sieh wrote: >> 6 different throws on each of two sided dice gives us 36 possible throws. >> >> Possible combinations equalling 7: >> >> Die 1 Die 2 >> 1 6 >> 2 5 >> 3 4 >> 4 3 >> 5 2 >> 6 1 >> >> Total combinations: 6 >> Probability = combinations equalling 7 / all possible combos >> = 6 / 36 = 1 / 6 = 16.6%. >> >> Following these calculations, rolls of 2 or a 12 would each have a >> probability 1 / 36. I agree that these are much less probable than >> rolling a 7 (the most probable roll with two six sided dice), but it seems >> that 1 / 6 is still against the odds, if you consider "against the odds" >> to mean less than 50%. > Wow, you are right! > > What was I thinking? > > Well, I was working off the fact that in games involving two dice, 7 is > the middle of the bell curve. I was erroneously thinking in terms of the > odds of rolling >= 7 or <= 7 (which is a 58% probability), rather than > just 7. > > With regard to the text I was also puzzled as to why a 7 would mean death, > when, for example, there are 10 men. Up until the moment I typed it in, I > sort of thought there were only 7 men, and the dice were saying how many > would die (all, in this case); but the dice tell a group fate, not a > fractional amount (all die or none die). On my first reading I thought he > was supposed to roll a number related to the number of crewmen, like, say > = 8 (42% chance). > > Even as I was typing it in this evening, and there was a glimpse of the > truth (that rolling a 7 really is a 1/6 chance), I veered away from this > and into the notion "Why not just use one die, if one-in-six is the > desired probability -- then the roll of a =1= would make the whole thing > quite obvious." And the waste of a perfectly nice bellcurve (as opposed > to the "flat" curve of a single die)! > > (The reason why one-in-six is important is made clear in the text: that is > the fatality rate for sunmen.) > > The reason why a 7 means death is because that is the only way to squeeze > out a 1 in 6 chance out of two dice! > > Anyway, I was wrong. Thanks for correcting me! (I still wonder why > Harness would choose to use =two= dice when one die would work better. > Well, work better for =me=, at least!) Addendum: we both arrived independently at the notion that Harness is probably talking about the dice game "craps," which, in the pre-wargaming/pre-rpg world, was the most common exposure to dice games. =mantis= Sirius Fiction Has Moved To http://www.siriusfiction.com/ ---