"We therefore have little doubt that if one of the jurors during the trial falls below the standards expected of a juror, the other jurors will report that to the judge during the trial and before the verdict. That is the presumption upon which this court should act, if the complaint is first made after the taking of the verdict. Inquiries should therefore not be ordered in such cases and the finality of the verdict accepted, absent other strong and compelling evidence. To do otherwise is neither fair nor just. …"