问题如下：
Assuming that Company A's profit and loss satisfy a normal distribution, its annual average value is $30 million and its standard deviation is $10 million. Which of the following statements about the calculation and interpretation of the 95% VaR value is correct?
选项：
A.5% probability that the company will lose at least $13.5 million.
B.5% probability that the company will earn at least $13.5 million.
C.95% probability that the company will lose at least $13.5 million.
D.95% probability that the company will earn at least $13.5 million.
解释：
D is correct.
考点：Parametric Estimation Approaches
解析：95%的VaR=30-1.65*10=13.5m
这道题的计算结果非常特殊，VaR值计算结果为正，无需取绝对值，也就是说有95%的概率盈利至少为13.5million。
老师讲的时候，VAR=-mean+1.645（分为点）*σ。
但是做题的时候，VAR又等于mean-1.645（分为点）*σ
var到底怎么算？
