Is this Bayesian Network Probability calculation correct?












1












$begingroup$


I think I understand how to calculate BN and why it is so, but complex net still confuses me. Currently how I understand it is that, if there is any 'result' variable in the probability, it can be calculated by converting it to P(result|cause)P(cause). So I assumed in this bayesian network (A,B → C → D,E), if you want to get P(B,E), every parent and grand parent of B and E should be considered. As B doesn't have parent, only the (grand) parent of E (A,C) will hop in, and finally it can be calculated as :



P(B,E)
= P(B,E,A,C)+P(B,E,~A,C)+P(B,E,A,~C)+P(B,E,~A,~C)



The joint probability would be :



P(B,E,A,C) = P(B)P(A)P(C|A,B)P(E|C)



The rest of them are calculated the same way. I'd like to check if this calculation and my understanding is right. Thank you!










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$endgroup$

















    1












    $begingroup$


    I think I understand how to calculate BN and why it is so, but complex net still confuses me. Currently how I understand it is that, if there is any 'result' variable in the probability, it can be calculated by converting it to P(result|cause)P(cause). So I assumed in this bayesian network (A,B → C → D,E), if you want to get P(B,E), every parent and grand parent of B and E should be considered. As B doesn't have parent, only the (grand) parent of E (A,C) will hop in, and finally it can be calculated as :



    P(B,E)
    = P(B,E,A,C)+P(B,E,~A,C)+P(B,E,A,~C)+P(B,E,~A,~C)



    The joint probability would be :



    P(B,E,A,C) = P(B)P(A)P(C|A,B)P(E|C)



    The rest of them are calculated the same way. I'd like to check if this calculation and my understanding is right. Thank you!










    share|cite|improve this question









    $endgroup$















      1












      1








      1





      $begingroup$


      I think I understand how to calculate BN and why it is so, but complex net still confuses me. Currently how I understand it is that, if there is any 'result' variable in the probability, it can be calculated by converting it to P(result|cause)P(cause). So I assumed in this bayesian network (A,B → C → D,E), if you want to get P(B,E), every parent and grand parent of B and E should be considered. As B doesn't have parent, only the (grand) parent of E (A,C) will hop in, and finally it can be calculated as :



      P(B,E)
      = P(B,E,A,C)+P(B,E,~A,C)+P(B,E,A,~C)+P(B,E,~A,~C)



      The joint probability would be :



      P(B,E,A,C) = P(B)P(A)P(C|A,B)P(E|C)



      The rest of them are calculated the same way. I'd like to check if this calculation and my understanding is right. Thank you!










      share|cite|improve this question









      $endgroup$




      I think I understand how to calculate BN and why it is so, but complex net still confuses me. Currently how I understand it is that, if there is any 'result' variable in the probability, it can be calculated by converting it to P(result|cause)P(cause). So I assumed in this bayesian network (A,B → C → D,E), if you want to get P(B,E), every parent and grand parent of B and E should be considered. As B doesn't have parent, only the (grand) parent of E (A,C) will hop in, and finally it can be calculated as :



      P(B,E)
      = P(B,E,A,C)+P(B,E,~A,C)+P(B,E,A,~C)+P(B,E,~A,~C)



      The joint probability would be :



      P(B,E,A,C) = P(B)P(A)P(C|A,B)P(E|C)



      The rest of them are calculated the same way. I'd like to check if this calculation and my understanding is right. Thank you!







      probability bayesian conditional-probability bayesian-network






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      asked Dec 12 '18 at 16:26









      PuffedRiceCrackersPuffedRiceCrackers

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          For the DAG: $$begin{array}{ccc}A&&&&B\&searrow&&swarrow \&&C\&swarrow&&searrow\D&&&&Eend{array}$$



          Then, yes,$$P_{B,E}=sum_{A,C}P_AP_BP_{Cmid A, B}P_{Emid C}$$






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            $begingroup$

            For the DAG: $$begin{array}{ccc}A&&&&B\&searrow&&swarrow \&&C\&swarrow&&searrow\D&&&&Eend{array}$$



            Then, yes,$$P_{B,E}=sum_{A,C}P_AP_BP_{Cmid A, B}P_{Emid C}$$






            share|cite|improve this answer











            $endgroup$


















              0












              $begingroup$

              For the DAG: $$begin{array}{ccc}A&&&&B\&searrow&&swarrow \&&C\&swarrow&&searrow\D&&&&Eend{array}$$



              Then, yes,$$P_{B,E}=sum_{A,C}P_AP_BP_{Cmid A, B}P_{Emid C}$$






              share|cite|improve this answer











              $endgroup$
















                0












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                0





                $begingroup$

                For the DAG: $$begin{array}{ccc}A&&&&B\&searrow&&swarrow \&&C\&swarrow&&searrow\D&&&&Eend{array}$$



                Then, yes,$$P_{B,E}=sum_{A,C}P_AP_BP_{Cmid A, B}P_{Emid C}$$






                share|cite|improve this answer











                $endgroup$



                For the DAG: $$begin{array}{ccc}A&&&&B\&searrow&&swarrow \&&C\&swarrow&&searrow\D&&&&Eend{array}$$



                Then, yes,$$P_{B,E}=sum_{A,C}P_AP_BP_{Cmid A, B}P_{Emid C}$$







                share|cite|improve this answer














                share|cite|improve this answer



                share|cite|improve this answer








                answered 2 days ago


























                community wiki





                Graham Kemp































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