问题如下图：
选项：
A. 
B. 
C. 
解释：
NO.PZ2017092702000103问题如下 The lognormstribution is a more accurate mol for the stribution of stoprices ththe normstribution because stoprices are:A.symmetrical.B.unbounC.non-negative. C is correct. A lognormstributevariable ha lower bounof zero. The lognormstribution is also right skewe whiis a useful property in scribing asset prices对数正态分布变量的下限为零。 对数正态分布也是右偏的，这是描述资产价格的一个有用的特性。 用lognormal为什么不选a呢
NO.PZ2017092702000103 是不是老师讲到的国内股票有一个涨跌幅度的限制呀？
NO.PZ2017092702000103 unboun non-negative. C is correct. A lognormstributevariable ha lower bounof zero. The lognormstribution is also right skewe whiis a useful property in scribing asset prices为什么lognormal的取值范围和右偏,可以很好的衡量stoprice或asset price呢 谢谢
bounfrom zero 不是说一定会大于0吗？？为啥不选B呢
