paizo.com Recent Posts in Math question for attack roll paizo.com Recent Posts in Math question for attack roll 2019-11-02T01:52:52Z 2019-11-02T01:52:52Z Re: Forums: Rules Discussion: Math question for attack roll NielsenE https://paizo.com/threads/rzs42tsx?Math-question-for-attack-roll#4 2019-11-02T21:43:26Z 2019-11-02T02:06:30Z <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 &mdash; what's the chance of both rolls being 7 or lower.</p> <p>Chance of 1 roll being 7 or lower: 35% <br /> Chance of both rolls being 7 or lower : 0.35^2 = 12.25% <br /> 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% NielsenE 2019-11-02T02:06:30Z Re: Forums: Rules Discussion: Math question for attack roll Razgriz 1 https://paizo.com/threads/rzs42tsx?Math-question-for-attack-roll#3 2019-11-02T21:43:25Z 2019-11-02T02:04:05Z <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 1 2019-11-02T02:04:05Z Re: Forums: Rules Discussion: Math question for attack roll Mellored https://paizo.com/threads/rzs42tsx?Math-question-for-attack-roll#2 2019-11-02T02:03:50Z 2019-11-02T02:01:38Z <p>1-(35% &bull; 35%) = 0.8775</p> <p>87.75%</p> 1-(35% * 35%) = 0.8775 87.75% Mellored 2019-11-02T02:01:38Z Forums: Rules Discussion: Math question for attack roll Atalius https://paizo.com/threads/rzs42tsx?Math-question-for-attack-roll#1 2019-11-02T01:52:52Z 2019-11-02T01:52:52Z <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. Atalius 2019-11-02T01:52:52Z