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eyn · 2024年12月19日

B为什么不对?

NO.PZ2024082801000009

问题如下:

Question An analyst is comparing the out-of-sample forecasting performance of an AR(1) model and an AR(2) model for monthly inflation rates. Which of the following metrics is the most appropriate for making this comparison?

选项:

A.A. R2 B.B.Durbin–Watson statistic C.C.Root mean squared error

解释:

  • A is Incorrect because a model's R2 measures how much of the variation in the dependent variable is attributable to the independent variable(s), not the relative difference in the out-of-sample forecasting performance between models.

  • B is Incorrect because a model's Durbin–Watson statistic tests whether the regression errors are serially correlated, not whether the out-of-sample forecasting performance of one model is better than that of another model.

  • C is Correct because, typically, we compare the out-of-sample forecasting performance of forecasting models by comparing their root mean squared error (RMSE), which is the square root of the average squared error. The model with the smallest RMSE is judged the most accurate.

RT

1 个答案

品职助教_七七 · 2024年12月20日

嗨,从没放弃的小努力你好:


可以从下面的两个角度排除B选项。

1)Durbin–Watson test的适用范围是多元回归。本题的两个方程都是AR模型,从方程的形式上可以去直接排除B选项;

2)本题的目的是“comparing...performance”,即对比两个模型的表现。DW test用于检验一个模型有没有序列相关,无法去对比两个不同的模型。

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