Outliers and Influential Points
Cannot be both an influential point and regression outlier
Outlier in the X-direction
Outlier in the X-direction
With x-direction data points only
Q1 - 1.5(IQR)
Q3 + 1.5(IQR)
Outlier in the Y-direction
Outlier in the Y-direction
With y-direction data points only
Q1 - 1.5(IQR)
Q3 + 1.5(IQR)
Influential Point
Influential Point
changes slope and increases r
points that are outliers in the x direction of a scatterplot are often influential for the least-squares regression line
Regression Outlier
Regression Outlier
distance from LRSL
real outliers that do not fit the line
use the absolute value of the residuals list
