Conclusions from the Youden plot

We can make the following conclusions from the Youden plot.
 In the upper left corner are the interaction term
X1*X3 and the main effects X1 and X3.
 In the lower right corner are the main effects X2 and
X7 and the interaction terms X2*X3
and X1*X2.
 The remaining terms are clustered in the center, which
indicates that such effects have averages that are
similar (and hence the effects are near zero),
and so such effects are relatively unimportant.
 On the far right of the plot, the confounding structure is
given (e.g., 13: 13+27+46), which suggests that the information
on X1*X3 (on the plot) must be tempered with the
fact that X1*X3 is confounded with
X2*X7 and X4*X6.
