习题：
　　Exercise:
　　Left-skewed distributions exhibit:
　　A.      Greater mass to the left of the expected value
　　B.      Greater mass to the right of the expected value
　　C.      A longer tail to the right of the distribution
　　D.      Greater mass close to the expected value
　　解析：
　　Answer: B
　　Explanation: Left-skewed distributions are those with a longer tail to the left side of the distribution, and whose mass is to the right of the expected value.
　　知识点：
　　Skewness
　　Skewness, or skew, refers to the extent to which a distribution is not symmetrical. The skewness of a normal distribution is equal to zero.
　　A positively skewed distribution is characterized by many outliers in the upper region, or right tail. A positively skewed distribution is said to be skewed right because of its relatively long upper (right) tail.
　　A negatively skewed distribution has a disproportionately large amount of outliers that fall within its lower (left) tail. A negatively skewed distribution is said to be skewed left because of its long lower tail.
　　(Outliers are observations with extraordinarily large values)
　　对自学的考生来说，听辅导课是必不可少的，在网课老师的指导下，学员自己去精读钻研，才能加深对FRM知识的理解，牢固掌握应考知识。体验免费课程
        FRM考试在线高清视频指导