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410140980 · 2022年11月03日

老师VaR的回测检验不是双尾吗

NO.PZ2018122701000037

问题如下:

A risk manager is analyzing a 1-day 99% VaR model. Assuming 225 days in a year, what is the maximum number of daily losses exceeding the 1-day 99% VaR that is acceptable in a 1-year backtest to conclude, at a 95% confidence level, that the model is calibrated correctly?

选项:

A.

3

B.

5

C.

8

D.

10

解释:

B is correct.

考点:Backtesting VaR

解析:The risk manager will reject the hypothesis that the model is correctly calibrated if the number x of losses exceeding the VaR is such that: 12\frac12

where p represents the failure rate and is equal to 1 - 99%, or 1%; and T is the number of observations = 225. And z = 1.96 is the two-tail confidence level quantile. If: x0.01×2250.01×(10.01)×225=1.96\frac{x-0.01\times225}{\sqrt{0.01\times(1-0.01)\times225}}=1.96

Then, x = 5.18. So the maximum number of exceedances would be 5 to conclude that the model is calibrated correctly.

95%的双尾检验对应的分位点不是1.65嘛,解析用的是1.96那不变成单尾了

1 个答案

pzqa27 · 2022年11月03日

嗨,爱思考的PZer你好:


同学你好,

这个题中,是双尾,双尾95%, 一个尾巴2.5%,对应1.96

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