我有一个数据框，有两列，一列是非连续变量（类型），一列是连续变量。如下：
type
[1] yes no no no no no yes yes no no no yes no yes no no no yes yes no yes yes
[23] no no no yes yes no no no no no yes yes no no no no yes no yes no no no
[45] yes yes no yes yes no no yes yes yes yes yes yes yes yes yes yes no yes yes no yes
[67] no no yes no no yes no no no no no no no no yes no yes no no no
a
[1] 3.9791315 1.6858251 2.2258789 2.3652999 1.3343428 2.0747936 1.8964374 8.5356289
[9] 4.2811201 2.2506607 2.5138663 10.7579693 1.6966975 5.9082100 0.6069126 1.7349567
[17] 6.7924184 1.2684428 2.4669286 1.5680604 1.8562952 6.2490262 3.8042861 0.9228999
[25] 0.7882594 0.7619779 4.9431538 1.8048185 2.2159644 3.1923903 0.8142719 1.3849706
[33] 1.6258009 8.9607262 6.8649349 5.5868721 2.0129583 3.0149273 4.7473429 1.4603519
[41] 6.3015085 1.1729423 1.2355456 8.8158084 1.4836212 2.3153738 2.3725520 2.1524332
[49] 14.2123502 5.0292601 0.6249852 0.6975495 2.9222584 2.2418207 1.7731882 1.9099612
[57] 2.3212481 2.3382343 0.6357407 0.6134000 4.9191728 2.0013811 1.7896485 0.9869889
[65] 2.3502840 2.5656680 0.8355163 1.6570806 1.4661763 0.5070523 2.2468655 6.3530850
[73] 1.9984940 2.2748529 1.5601164 1.3341472 1.7188704 1.0099246 1.3376718 4.9298256
[81] 23.9879645 2.3976487 3.1628499 1.8186009 1.0607853 0.9095033
请教如何设定cutoff值尽可能分开两组，使得p值最小。