In your opinion. I'd much rather there was some sort of minimum standard of education needed. I hate the thought of being wrongly convicted and my life being decided by a bunch of sun readers whose only experience of decision making is the xfactor.
Trials by jury are decided purely on evidence, we need to make sure the evidence is viewed by people that can actually understand it. This is even evidenced when the judge will sometimes urge the jury to make a particular decision.
I was going to wait until you had replied, but I won't... The trials are based on the evidence. Both the facts, and how the facts are presented. That witness just told you X did Y. But was he lying? Did he look like he was lying? Did his voice waver? Did they get any of it wrong?
The jury are asked to use their worldly knowledge of people when judging evidence - but only when determining evidence from people. If it is on paper, it is black and white. If it is someone's writing, you cannot determine who wrote it - even if you really are a handwriting expert you are asked to not consider it. But if it is someone
telling you/the court something, you are expected to judge if it is the truth or not.
You should also have realised that it is the job and responsibility of the Barristers and the Judge to ensure the jury understand the evidence and the relevant pieces of law. It is, in fact, the primary purpose of Barristers to do exactly this, and is a very important role for the Judge - the only role more important to the Judge is to ensure the defendant(s) has a fair trial, which "ensuring the jury understand the evidence" is a big part of no less.
The very same saying "putting it in lay-man's terms" comes from this very role Barristers play, by the way.
The trial is not just the prosecution dumping folders of evidence in front of you and saying "There you go, read that lot" and then the defence doing the same. The only reason trials last as long as they do is because everything has to be explained in the smallest detail to the jury, to completely remove the chance that some/all of them "just don't get it". The jury are invited to ask questions if they do not understand anything. They are constantly reminded that if any of the other jurors might cause an issue they should inform the judge, and can do so anonymously.