To convict someone of a crime, you cannot have any doubt at all that they are not guilty. To convict someone guilty beyond reasonable doubt is very sensitive, especially in murder cases.
It effected the verdict in the movie because most of the men was just sure the subject was guilty of killing his father until talking about it. After discussing the trial most of the jury had reason to believe the evidence could be doubted. The judge made it very clear to the jury in the beginning how important their role was, and how crucial it was to 100% know there was no reasonable doubt before sentencing the kid with murdering his father.
Overall I must give the movie a C, I thought it was hard to keep following and their conversation was difficult to understand at time. My personal favorite part about the movie was how it ended still making you wonder. I cannot help but think of cases like Casey Anthony and OJ Simpson, where most of our nation believe both to be guilty yet that is not how it went in court. I agree in this movie there was a lot of loop holes that did not add up to be able to convict the kid. All though it is not impossible that all the timing was in his favor and that he truly was