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lion · 2023年05月08日

求解释

NO.PZ2020011303000086

问题如下:

Suppose that the current volatility estimate is 3% per day and the long-run average volatility estimate is 2% per day. What are the volatility estimates in ten days and 100 days in a GARCH (1,1) model where ω= 0.000002, α= 0.04, and β= 0.94?

解释:

The expected variance rate in ten days is 0.02^2 + (0.04 + 0.94)^10 (0.03^2 0.02^2) = 0.000809, which corresponds to a volatility of 2.84%. The expected variance rate in 100 days is 0.02^2 + (0.04 + 0.94)^100 (0.03^2 0.02^2) = 0.000466, which corresponds to a volatility of 2.16%.

题目问:现在是volatility=3%long-run average volatility=2%,利用GARCH(11)来计算10天和100天的volatilityω=0.000002, α= 0.04, and β= 0.94

10volatility=[0.02^2 + (0.04 + 0.94)^10 (0.03^2– 0.02^2)]^0.5 = 2.84%.

100volatility=[0.02^2 + (0.04 + 0.94)^100 (0.03^2 – 0.02^2)]^0.5 =2.16%.

为什么和上一题不一样

1 个答案

品职答疑小助手雍 · 2023年05月09日

同学你好,这提条件是有点问题,1-0.04-0.94=0.02,系数等于0.02,可是又给了w=0.000002,VL=2%,这样算出来系数相加就不等于1了。

当然它考察的点是另一个公式,原版书提了一下如下图,不过我觉得不是很重要,可以忽略。