魔兽世界复仇圣印触发机率问题

本着骑士区一贯的求实精神,进行了如下数学计算:

首先,我们要对复仇圣印的特性有所了解:
1:复仇圣印触发是基于PPM机制的，且PPM=20;
2:复仇圣印击中后如果成功刷新DOT,可维持15秒,只要在15秒内再次成功刷新DOT即可保持;
3:复仇圣印必须在武器成功命中目标后才可能刷新DOT.

----------------------------------+----------不同物理攻击命中率下DOT丢失概率---------+
武器速度 刷新率 可攻击次数 100% 95% 90% 85% 80%
1.5 50% 9 0.20% 0.30% 0.46% 0.69% 1.01%
1.6 53.3% 9 0.10% 0.28% 0.44% 0.46% 0.67%
1.7 56.7% 8 0.12% 0.20% 0.33% 0.52% 0.79%
1.8 60% 8 0.06% 0.12% 0.20% 0.33% 0.53%
1.9 63.3% 7 0.09% 0.16% 0.27% 0.45% 0.71%
2.0 66.7% 7 0.05% 0.09% 0.16% 0.29% 0.48%
2.1 70% 7 0.02% 0.05% 0.09% 0.18% 0.32%
2.2 73.3% 6 0.04% 0.08% 0.16% 0.29% 0.50%
2.3 76.7% 6 0.02% 0.04% 0.09% 0.18% 0.33%
2.4 80% 6 0.01% 0.02% 0.05% 0.11% 0.22%
2.5 83.3% 5 0.01% 0.04% 0.10% 0.21% 0.41%
2.6 86.7% 5 0.00% 0.02% 0.05% 0.13% 0.27%
2.7 9