概率方差D(X)公式简介：Mo Xiaoqi looked at the true dragon's blood in her hand, and thought that she had tried so hard to get this true dragon's blood, but she didn't expect that Ao Zhiyun saw through it, and she didn't succeed.
Mo Xiaoqi looked at the true dragon's blood in her hand, and thought that she had tried so hard to get this true dragon's blood, but she didn't expect that Ao Zhiyun saw through it, and she didn't succeed.
