Chapter 9

Question 1

outlier

Answer 1

any data point that stands away from the others can be called an outlier. In regression, outliers can be extraordinary in two ways; by having a large residual or by having high leverage.

Question 2

leverage

Answer 2

data points whose x-values are far from the mean of x are said to exert leverage on a linear model.

Question 3

influential point

Answer 3

if omitting a point from the data results in a very different regression model, then that point is called an influential point,

Question 4

lurking variable

Answer 4

A variable that is not explicitly part of a model but affects the way the variables in the model appear to be related is called a lurking variable.