Sad? Nay, brother! Rejoice in the beauty and majesty that is MATHEMATICS!
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| Percentages of percentages http://worldworksgames.com/forum/viewtopic.php?f=73&t=4966 |
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| Author: | Kane [ 08-28-2007, 11:40 AM ] |
| Post subject: | Percentages of percentages |
Alright, made some dice-level changes to my home-brew game system and was trying to figure something out. If, for example, I am rolling a D12 with a difficulty of 4, that gives me a 25% chance of failure. What if its two dice? Three dice? I have never taken statistic classes so am at a bit of a loss as to how to figure this out. |
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| Author: | pelthar [ 08-28-2007, 12:04 PM ] |
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Kane- Since each dice roll is independent of the other you essentially just have to multiply the individual odds together. Assuming you are counting succseses then the odds are: 2 Successes: (The odds for die 1 a succcess) * (The Odds for die 2 a success) = .75 * .75 = .5625 or 56.25% 0 Success: (the odds for die 1 a failure) * (the odds for die 2 a failure) = .25 * .25 = .0625 or 6.25% 1 Success: (The odds for die 1 a failure) * (The odds for die 2 a success) = .25 * .75 = .1857 or 18.75% (The odds for die 1 a SUCCESS) * (The odds for die 2 a FAIILURE) = .25 * .75 = .1857 or 18.75% So the total odds for 1 succes will be 18.75% + 18.75% = 37.5% -Pel (theoretical mathematics major) |
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| Author: | pelthar [ 08-28-2007, 12:10 PM ] |
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| Author: | Kane [ 08-28-2007, 01:00 PM ] |
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| Author: | pelthar [ 08-28-2007, 01:06 PM ] |
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| Author: | Kane [ 08-28-2007, 01:09 PM ] |
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| Author: | ScrubKai [ 08-28-2007, 07:25 PM ] |
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| Author: | pelthar [ 08-29-2007, 02:38 AM ] |
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Sad? Nay, brother! Rejoice in the beauty and majesty that is MATHEMATICS!
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| Author: | Kane [ 08-29-2007, 05:06 AM ] |
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Worst thing for me is that back in school, I took algebra early, but was so flustered by a bad teacher for geometry and alII, I gave up on math. I even did math tutoring, but like so many coaches, I failed at the actual application. |
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| Author: | Spoo [ 08-29-2007, 05:48 AM ] |
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If you want these probabilities for lots of dice, check out . |
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| Author: | SteveRB11 [ 08-30-2007, 05:57 PM ] |
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You also want and -- some baseline probability concepts good for doing such things calculating expected value outcomes when throwing a handful of different types of dice in D&D, Silent Death, etc. |
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| Author: | Kane [ 12-11-2007, 01:50 PM ] |
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| Author: | Spoo [ 12-11-2007, 05:05 PM ] |
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| Author: | Kane [ 12-11-2007, 10:28 PM ] |
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Ah, I see the mistake in my math. Thanks. Now then, 10% will be the minimum chance (10 on a D10) so I suppose allowing up to 10 dice may not be a bad idea. Just ran the chart for 10% and came up with just .1 repeating as you add more dice. Did I do something wrong here? One Success Chances D10s Diff +4(10%) 1 = 10% 2 = 11% 3 = 11.1% 4 = 11.11% 5 = 11.111% 6 = 11.1111% 7 = 11.11111% 8 = 11.111111% Also, not sure how to plug that into Excel properly. Any tips? |
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| Author: | Kane [ 12-11-2007, 11:09 PM ] |
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Ugh...this is hurting my head. So, I can get the formula to work to find out if at least 1 die will come up high enough, but what about ALL dice? Here is what it looks like from Excel One Success Chances D10s Diff +4(10%) 1 = 10% 2 = 19% 3 = 27% 4 = 34% 5 = 41% 6 = 47% 7 = 52% 8 = 57% 9 = 61% 10 = 65% I have NO clue how that works if the chart for ALL dice to succeed is All Succeed Chances D10s Diff +4(10%) 1 = 10% 2 = 1% 3 = 0.1% 4 = 0.01% 5 = 0.001% 6 = 0.0001% 7 = 0.00001% 8 = 0.000001% 9 = 0.0000001% 10 = 0.00000001% Or did I do that wrong too? 10% x 10%= 1%, 1% x 10%=0.1%...brain melting...ing...ing... |
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| Author: | Spoo [ 12-12-2007, 07:15 AM ] |
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| Author: | Kane [ 12-12-2007, 08:14 AM ] |
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| Author: | Andorax [ 12-12-2007, 09:09 AM ] |
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| Author: | Kane [ 12-12-2007, 09:12 AM ] |
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| Author: | Kane [ 12-12-2007, 09:18 AM ] |
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| Author: | Spoo [ 12-12-2007, 06:51 PM ] |
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| Author: | Kane [ 12-12-2007, 09:11 PM ] |
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| Author: | pelthar [ 12-13-2007, 06:27 AM ] |
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Yeah. it gets really hairy doing it by hand because you have to consider a lot of different combinations of successes and failures. |
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| Author: | Kane [ 12-13-2007, 08:43 AM ] |
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