paizo.com Recent Posts in Math question for attack rollpaizo.com Recent Posts in Math question for attack roll2019-11-02T01:52:52Z2019-11-02T01:52:52ZRe: Forums: Rules Discussion: Math question for attack rollNielsenEhttps://paizo.com/threads/rzs42tsx?Math-question-for-attack-roll#42019-11-02T21:43:26Z2019-11-02T02:06:30Z<p>You're asking for what's the probability that at least one roll out of two, is 8 or more? Its often simpler to express it as the failure case — what's the chance of both rolls being 7 or lower.</p>
<p>Chance of 1 roll being 7 or lower: 35%
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Chance of both rolls being 7 or lower : 0.35^2 = 12.25%
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1.0 minus that: 0.8775 = 87.75%</p>You're asking for what's the probability that at least one roll out of two, is 8 or more? Its often simpler to express it as the failure case -- what's the chance of both rolls being 7 or lower.
Chance of 1 roll being 7 or lower: 35%
Chance of both rolls being 7 or lower : 0.35^2 = 12.25%
1.0 minus that: 0.8775 = 87.75%NielsenE2019-11-02T02:06:30ZRe: Forums: Rules Discussion: Math question for attack rollRazgriz 1https://paizo.com/threads/rzs42tsx?Math-question-for-attack-roll#32019-11-02T21:43:25Z2019-11-02T02:04:05Z<p>You take the 35% chance of failing the first.</p>
<p>Then you calculate 65% of 35% which gives you 22.75%. This is the chance that you'll get less than 8 the first time but then get 8 or more the second.</p>
<p>Now you either add 65% + 22.75% or you subtract 100% by (35% - 22.75%). Both should give you 87.75% which is the total chance of you succeeding at either roll.</p>You take the 35% chance of failing the first.
Then you calculate 65% of 35% which gives you 22.75%. This is the chance that you'll get less than 8 the first time but then get 8 or more the second.
Now you either add 65% + 22.75% or you subtract 100% by (35% - 22.75%). Both should give you 87.75% which is the total chance of you succeeding at either roll.Razgriz 12019-11-02T02:04:05ZRe: Forums: Rules Discussion: Math question for attack rollMelloredhttps://paizo.com/threads/rzs42tsx?Math-question-for-attack-roll#22019-11-02T02:03:50Z2019-11-02T02:01:38Z<p>1-(35% • 35%) = 0.8775</p>
<p>87.75%</p>1-(35% * 35%) = 0.8775
87.75%Mellored2019-11-02T02:01:38ZForums: Rules Discussion: Math question for attack rollAtaliushttps://paizo.com/threads/rzs42tsx?Math-question-for-attack-roll#12019-11-02T01:52:52Z2019-11-02T01:52:52Z<p>Sorry math was never my strong suit, I'm trying to figure out the probability of rolling an 8 or more on a D20 with two chances at it. I know for one chance it's 65% but how would you figure it out for two rolls? Thanks all for the help.</p>Sorry math was never my strong suit, I'm trying to figure out the probability of rolling an 8 or more on a D20 with two chances at it. I know for one chance it's 65% but how would you figure it out for two rolls? Thanks all for the help.Atalius2019-11-02T01:52:52Z