As we can see from the note 1, the line passes points (0,20) &(1,80) means that the coloum defends right. When p is less than .7, the coloum will act so as to minimize the row's percent success which means the left part of the blue line in the graph. That part of the blue line is on the line described by the note 1.Then we can conclude the coloum will defnd right when p is less than .7. Thus, the original article is wrong.

谢谢回复:)