Well,I think I should use another term instead of this.
I forgot risk/reward refers to expected return.
The original purpose of this question is since the tail event is much higher than normal distribution would suggest,the 1:2(instead of prevailing 2:1)risk/reward ratio might not be 1:2 at last.
What should I do?Maybe I should use 2:1 so it is more understandable..?