Difference between conclusion and decision

 
From what I understand, a conclusion is reached after all the parameters lead to it. A decision is made when there are several conclusions.
There is a video by Yeshayahu Leibowitz called ‘Yeshayahu Leibowitz – Conclusions and Decisions,’ but it requires an unknown amount of time.
Is it possible to decide in favor of a conclusion that is not highly probable?
What is the difference between a conclusion and a decision?
thanks