how are mediation scores measured and correlated is $c$ a binary variable if a variable is a binary variable, it should increase is mediation and difference scores correlated difference score definition vs binary iv which iv is a binary variable? why is $a$ a binary variable is $A$ a binary iv what is a$ does mediation increase b$ what is the relationship between a$ and $e when does $A$ cause increase vs increase in $c$ is mediation a binary variable how is $a$ correlated with $c$ in mediation? what is the difference between c$ and b$ what is the relationship between mediator score and mediation score are mediator scores correlated why is median a$ a binary variable is $A$ a binary variable? what is $delta b$ and $delta c$