NO.PZ2023040502000020
问题如下：
Interpreting the
graph, Reyes states:
"The
presence of heteroskedasticity is indicated when there is a systematic
relationship between the values of residuals and the independent variable. It
is difficult to see such a systematic relationship in Exhibit 2. Therefore,
heteroskedasticity does not appear to be a problem in this regression."
Reyes' interpretation of the graph in Exhibit 2 is best described as:
选项：
A.correct
incorrect because the effects of heteroskedasticity
are, in a regression such as this one, hidden by the negative slope of the
regression line
incorrect because heteroskedasticity is indicated when
there is not a systematic relationship between the residuals and the
independent variable
解释：
The presence of heteroskedasticity is indicated when a
systematic relationship exists between the residuals and the independent
variable. It is difficult to see such a systematic relationship in Exhibit 2.
Therefore, heteroskedasticity does not appear to be a problem in this
regression.
老师好，有两个问题请教一下：
1.判断是否存在条件异方差，我理解的是：图里的横轴是否应该为自变量，纵轴是方差。如果图里没有呈现明显趋势说明不存在条件异方差现象。这样理解对吗？
那么这道题图里的横轴和纵轴分别是解释变量X和被解释变量Y？我做题的时候以为问题出在横纵轴上，就是这样判断错的。
2.有一些常见的违反假设情形的散点图、QQ图啥的以及通过图判断是否存在问题一直容易做错，能麻烦老师通过图举例总结一下吗？谢谢！
