Table 3.

The joint probability of the response variables

$Y_1$	$Y_2$		Total
	$Y_2=1$	$Y_2=0$
$Y_1=1$	$p_{11}$	$p_{10}$	$p_{1+}$
$Y_1=0$	$p_{01}$	$p_{00}$	$p_{0+}=1-p_{1+}$
Total	$p_{+1}$	$p_{+0}=1-p_{+1}$	$p_{++}=1$