Note that since the simple correlation between the two sets of residuals plotted is equal to the partial correlation between the response variable and " X " i, partial regression plots will show the correct strength of the linear relationship between the response variable and " X " i.
22.
DN model offers a necessary condition of a causal explanation successful prediction but not sufficient conditions of causal explanation, as a universal regularity can include spurious relations or simple correlations, for instance " Z " always following " Y ", but not " Z " because of " Y ", instead " Y " and then " Z " as an effect of " X ".
