Post/Author/DateTime	Post
Mogl the Barbarian 07-18-03, 02:24 PM	A player in our group, instead of rolling a d20, rolls a d6-d10 combo (the d6 to determine the high/low result on the d10; so for example if he rolled a 4 on the d6 and a 2 on the d10 the result would be a 12). He assures me this method provides the same randomness as a standard d20. I said fine until he rolled 3 "20's" in a row. I'm now considering Rule 0. Does anyone have any proof for or against the validity of this alternate method? I'm horrible at math, so if you could use kindergarten language I'd appriciate it. Thank you.
Jagyr Ebonwood 07-18-03, 02:27 PM	Lets see...that's 60 possible combinations... I'll work on it and get back to you.
Tristan Avon Granvania 07-18-03, 02:30 PM	Well, let's see.... 30 possible combinations that result in 1-10, and 30 possible combinations that result in 11-20... all with the exact same odds of coming up. I've seen triple 20s on a d20. Not often... but more than once. ~Evil DM
inci 07-18-03, 02:35 PM	whats the point to do it? it is the same, as stated above.
Erus 07-18-03, 02:37 PM	Superstition, or maybe he got a set of fixed D6s off Ebay.... 2 6 sides, no 1 :OMG! Erus.
King of Diamonds 07-18-03, 02:39 PM	If he is doing this because he doesnt want to roll a d20 i would disalow it however if nobody at your table has a d20 that is something i would concider doing
Flak 07-18-03, 02:44 PM	He has exactly the same odds of getting a 20 on that as he does on a d20...just watch to be sure he isn't fudging rolls.
Jagyr Ebonwood 07-18-03, 02:57 PM	[Edit] :blush::blush::blush: I retract that, my calculations were incorrect... Damn you, Microsoft Word! Still, you may want to get him a d20 just to be on the safe side.
Ulorian 07-18-03, 03:00 PM	Statistically, it's the same odds as rolling a d20. Real-life, though, it's a lot easier to cheat while rolling a die with larger faces i.e 'dropping' a die instead of properly rolling it so that it lands in a predictable way. If he insists on rolling this way, I'm going to go out on a limb and say that this guy is trying to cheat. Also, as someone else suggested, check the dice he is using to make sure they aren't trick dice. I had a player once who would blatantly cheat like this all the time. He must have practiced for hours on end, because he was an absolute wizard at this. He would palm his dice a certain way and toss them so that they would fiip only once while in the air and would always land showing a max roll. We used to roll our dice into a shoebox (so that the dice wouldn't roll off the table, as often happened). I ruled that the roll didn't count unless the dice hit at least one side of the box after hitting the bottom and that the dice had to travel at least half the length of the shoebox on a toss. Amazingly, he very suddenly was no longer able to achieve maximum damage with his longsword on every other hit :D.
Ulorian 07-18-03, 03:04 PM	Originally posted by Jagyr Ebonwood Actually, you are all wrong. I thought it was the same too (it looks like it at first glance, dunnit?), but it's not when you examine it. When you roll that combination, you have- A 33% chance of rolling a: 2, 4, 6, 8, 10, 11, 13, 15, 17, 19 A 66% chance of rolling a: 1, 3, 5, 7, 9, 12, 14, 16, 18, 20 So, unless my calculations are incorrect, rolling this way IS different from rolling a d20. The odds do even out somewhat... But still, he's essentially rolling a d30 with one ten and two 20s... You may want to get him a d20 just to be on the safe side. Your calculations are incorrect. Look at it this way: you roll a d10 and get a number from 1 to 10. You roll a d6 and if the result is 1-3 (50% chance) you add zero to the roll of the d10, and if the result is 4-6 (50% chance) you add 10 to the roll of the d10.
Flak 07-18-03, 03:07 PM	Originally posted by Jagyr Ebonwood Actually, you are all wrong. I thought it was the same too (it looks like it at first glance, dunnit?), but it's not when you examine it. When you roll that combination, you have- A 33% chance of rolling a: 2, 4, 6, 8, 10, 11, 13, 15, 17, 19 A 66% chance of rolling a: 1, 3, 5, 7, 9, 12, 14, 16, 18, 20 So, unless my calculations are incorrect, rolling this way IS different from rolling a d20. The odds do even out somewhat... But still, he's essentially rolling a d30 with one ten and two 20s... You may want to get him a d20 just to be on the safe side. 50% above ten, 50% ten or below, then 1 in 10 for any of the numbers in a category. odds are even for any number.
Arbitrary Aardvark 07-18-03, 03:07 PM	Originally posted by Jagyr Ebonwood Actually, you are all wrong. I thought it was the same too (it looks like it at first glance, dunnit?), but it's not when you examine it. When you roll that combination, you have- A 33% chance of rolling a: 2, 4, 6, 8, 10, 11, 13, 15, 17, 19 A 66% chance of rolling a: 1, 3, 5, 7, 9, 12, 14, 16, 18, 20 So, unless my calculations are incorrect, rolling this way IS different from rolling a d20. Your calculations are incorrect. If the d6 is a 1, 2, or 3, take what is rolled on the d10 as the result. If the d6 is a 4, 5, or 6, add 10 to the d10 to get the result. I can't even figure out how you got your numbers. BTW, back in the old days (25+ years ago), d20s were labeled 1-10 twice. [The major reason for this is that d20s were originally used in pairs of differing colors to generate percentage results for various miniatures games.] We either rolled using the d6 and d10 method, or colored the dice in two-colors using fine-tip markers or crayon. (One set of 1-10, or 0-9 more likely, would be colored, and the other either left plain or colored differently.) Before rolling we would have to announce which color would be high. There was always some joker who wouldn't announce until after he rolled.
Jagyr Ebonwood 07-18-03, 03:14 PM	Wow, in the time it took me to triple check my calculations and do a quick edit, 3 people had told me I was wrong... :embarrass: I'm not sure how I messed it up, but I'm pretty sure it had to do either- a) listing the numbers 123456789012... 123456123456... rather than 123456789012... 111111111122... or b) microsoft word thinking my numbers were a bulleting format :rolleyes: Yes, the odds of a d20 = d10w/d6
Tzalice Minoladir 07-18-03, 03:34 PM	so what's the w for? :confused:
Tristan Avon Granvania 07-18-03, 03:43 PM	w/ means with. d10 w/d6 just like w/o means without. ~Evil DM
torchflame 07-18-03, 04:19 PM	Personally, I'd say get a reason from this person. I can't think of any logical reasons to roll a die combination to simulate a d20 roll. Could be superstition. Could be a tricky d6, always leaning him to 11+ I'm not sure if the statistics are exactly correct, though. There's a 10% chance you roll a 1 on said d10. There is then a 50% chance that it's an 11 or 1. all this adds up to a 5% chance. On a d20, there is a 5% chance that you roll any given number as well. Look at it this way. There are 10 possible outcomes above 10 with a d20. Likewise, there are 10 possible outcomes avove 10 with a combined roll, however, there are 30 different rolls above 10, whereas with the d20, there are only 10. Also, I would point out that there are 3 different rolls that garner a natural 20, as opposed to 1. The math still works out, since everything is *3, but there are more variables, which, to my mind, slightly unbalances the d20 method.
Sid_Patterson 07-18-03, 08:27 PM	Numerology aside, what the heck for? Has anyone answered that? I mean, if it doesn't slant the odds...if it doesn't change anything...what difference does it make. I'd say NO just because I'm not a numerologist and it would be wasting my time. I think some of you guys have too much time on your hands:rolleyes:
Mogl the Barbarian 07-18-03, 08:54 PM	Thanks, everybody, for the info - both the tech responses and the larger game issues. Nice to know there's a place to go when you need help.