以下是引用水模样在2007-8-31 20:40:00的发言:还有一个我没懂,请教 book4,p105的9题的解释,最后说:the overall risk of the portfolio should decrease, resulting in a lower standard deviation. Does that mean low risk, low SD; high risk, high SD? [em09] sd result in risk,so we can only say that the higher sd, the higt risk. |