Before revision: In this paper, the solution of the equity premium puzzle was given. First, the Arrow-Pratt measure of relative risk aversion for detecting the risk behavior of investors was questioned, and then a new tool  was developed to study the risk behavior of investors .
After revision: In this paper, the solution of the equity premium puzzle . Questioning the validity of the Arrow-Pratt measure of relative risk aversion for detecting the risk behavior of investors was questioned, and then a new tool was developed to study the risk behavior of investors .