Shaped like
Joint distribution: a probability value determined jointly by two random variables
Marginal distribution: the value obtained by extracting a single variable in the joint distribution, as shown in the figure above, the marginal distribution is equal to the addition of a row or a column P(Y=5)=P(X=10,Y=5)+P(X=12 ,Y=5)+P(X=15,Y=5)=0.05+0.07=0.04=0.16
Conditional probability in a joint distribution:
P{X=10|Y=6}=0.15/0.33
Independence of two-dimensional random variables:
independent of each other is equivalent to Pij = Pi x Pj