18/08/11 20:15:38.01 O/h5+IQW.net
A-Bag : Red-4 Blue-6
nonA-Bag : Red-5 Blue-4
A: picking A-Bag
B: picking Blue
P_Y(X)=P(X|Y)
P(A)=1/2
P(￢A)=1/2
P(A∩B)=P(A)P(B|A) = 1/2*6/10 = 0.3
= P(B)P(A|B)
P(B) = P(B|A)P(A) + P(B|￢A)P(￢A)= (1/2)*(6/10) + (1/2)*(4/9)=47/90
P(A)P(B)=1/2*47/90=47/180=0.2611111
P(A|B)=P(A)P(B|A)/P(B)
=P(A)P(B|A)/{P(A)P(B|A) + P(￢A)P(B|￢A)}
=(1/2*6/10) / (1/2*6/10 + 1/2*4/9)
= 27/47