What was one point of issue that caused some of the jury members to have doubt in 12 angry men?

After a heated discussion, the majority of jurors felt he was innocent having weighed the facts of the case and concluded that there was some margin for error in the case.

1) What does a jury call this margin of error? (Use alternate methods to assist you with this answer) ( this answer is worth 5 marks so saying the term and explaining it is important).

2) How would you describe this term to an individual who is sitting in on a trial for the first time?