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齐王木木 · 2023年10月23日

为什么不选a?

NO.PZ2023040502000046

问题如下:

Alicia wants to predict future quarterly sales for ABC Inc. She begins by running the following regression: ln Salest – ln Salest–1 = b0 + b1(ln Salest–1 – ln Salest–2) + εt.


Based on the regression output in Exhibit 2, what should lead Alicia to conclude that the Regression equation is not correctly specified?

选项:

A.

The Durbin–Watson statistic

B.

The t-statistic for the slope coefficient

C.

The t-statistics for the autocorrelations of the residual

解释:

The regression output in Exhibit 2 suggests there is serial correlation in the residual errors. The fourth autocorrelation of the residual has a value of 0.6994 and a t-statistic of 4.3111, which is greater than the t-statistic critical value of 2.02. Therefore, the null hypothesis that the fourth autocorrelation is equal to zero can be rejected. This indicates strong and significant seasonal autocorrelation, which means the Regression equation is misspecified.

题干问的是哪一项导致回归的模型是错误的

A选项里的dw法是用来检测非AR模型的 而题干列表里使用了dw法来检测ar模型 这样不就导致ar模型错误了吗

1 个答案

星星_品职助教 · 2023年10月24日

同学你好,

用什么方法去检测不影响模型本身的正确性,只会导致检测结果错误或者无效。

由于“dw法是用来检测非AR模型的”,所以在AR模型中DW法就是无效的,给不出任何结论。即使给出了DW数据也不需要看,由此不选A。