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.
Just as outliers influence some measures of location, they influence some measures of spread. When you have outliers, you may want to use the median or the trimmed or Winsorized mean as measures of central tendency (see Page on statisticalanalysisconsulting.com for more).