In regression analysis, an outlier is an observation whose
A) mean is larger than the standard deviation.
B) residual is zero.
C) mean is zero.
D) residual is much larger than the rest of the residual values.

Question

Quizplus · Accepted Answer

An outlier in regression analysis is defined as an observation whose residual, or the difference between its actual response value and predicted response value, is much larger than the rest of the residual values. Therefore, option D is the correct answer. The mean and standard deviation of an observation have no bearing on whether it is an outlier or not, so options A and C can be eliminated. Option B is also incorrect as a residual of zero would indicate a perfectly fitted model.

In Regression Analysis, an Outlier Is an Observation Whose