Red and yellow creates orange. Yellow and blue creates green. The secondary colors can be mixed further to create additional shades. Tertiary colors are the result of a primary and secondary color mixed together. For example, orange mixed with red creates red-orange.
An influential point is an outlier that greatly affects the slope of the regression line. One way to test the influence of an outlier is to compute the regression equation with and without the outlier. This type of analysis is illustrated below.
Thus, there is a distinction between outliers and high leverage observations, and each can impact our regression analyses differently. It is also possible for an observation to be both an outlier and have high leverage. Thus, it is important to know how to detect outliers and high leverage data points. Once we've identified any outliers and/or high leverage data points, we then need to determine whether or not the points actually have an undue influence on our model. This lesson addresses all these issues using the following measures: