题目
In order to forecast housing starts, your colleague Brett is going to use the following seasonal model that employs a regression on seasonal dummies:「huixue_img/importSubject/1564169388335173632.png」About this model, each of the following is true EXCEPT which is false?
选项
A.This model does not contain a trend
B.If the model includes twelve monthly seasons (January, February, ..., December) such that s = 12, then seasonal factor γ(5) is probably greater than either γ(1) or γ (12)
C.If the model includes four seasons (spring, summer, fall and winter) such that s = 4, then he should include four (4) seasonal dummy variables plus an intercept
D.If this is a quarterly model such that y(t) = γ(1) + γ(2)×D2 + γ(3)×D3 + 9.0×D4, and the standard error of the γ(4) = 9.0 coefficient is 15.0, then we can infer that average housing starts in the 4th quarter is not statistically different than average housing starts in the first quarter
答案
C
解析
If we include an intercept then we only want (s-1) dummy variables.我们只需要(s-1)个哑变量