Given the fact that A, B C, D are the input nodes and Quality is the output node. value of all input nodes can vary from 0 to 1.
closed as unclear what you're asking by Peter Flom♦ Mar 29 '17 at 11:10
Please clarify your specific problem or add additional details to highlight exactly what you need. As it's currently written, it’s hard to tell exactly what you're asking. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.
Welcome to CV!
First, Bayesian networks require you to give probability distributions for $A,B,C,D$ and $Q$=quality. Without this information we can't answer your question properly.
If you know this information, then edit your question above. Otherwise your first step in solving the problem is to find appropriate probability distributions for these variables.
Once you have these, you might be lucky and get a closed form solution. Otherwise you'll need to use a tool like Stan, JAGS, or BUGS to compute the solution.