What is the standard for appellate review regarding findings of fact?

In Cooper v. Cooper 2001 NFCA 4, Green, J.A. (as he then was), dealt extensively with the scope of appellate review regarding findings of fact; the following are excerpts from paragraphs 8 to 12: Different linguistic formulations have from time to time been used to describe the standard for appellate review. ... In essence, three grounds of intervention are postulated in these formulations: (i) Where the trial judge has committed an error of law ... This would include: (a) a wrong analysis or formulation of the applicable law or legal principle involved; (b) an improper application of a legal rule or principle to the established facts. No deference is accorded to the trial judge’s decision in this regard; his or her statement or application of the law is either correct or it is not. (ii) Where the trial judge has failed to comply with his or her duty to decide the case on all the evidence ... This would include: (a) failing to consider evidence essential to the outcome of the case; (b) giving consideration to evidence that is irrelevant or extraneous to the issue to which the legal principles are being applied; (c) misstating the evidence. (iii) Where the decision of the trial judge is not capable of being rationally supported by the relevant evidence adduced at trial ... This ground does not invite a reassessment, de novo, of the evidentiary record the appellate court, with a view to substituting its decision for that of the trial judge; rather, it is limited to a re-examination of the record to determine whether there was evidence upon which a reasonable trier of fact could have come to the conclusion he or she did. Grounds (ii) and (iii) relate to circumstances where appellate review may be had in circumstances where the complaint is with the factual basis for the decision. They are often compendiously described as requiring that the appellant demonstrate “palpable and overriding error” or “manifest error” by the judge in the assessment or appreciation of the evidence ... The narrow grounds for intervention in this regard reflect the principle of appellate deference to the decision of the trial judge on matters of fact. ... [A]bility to observe the witnesses in the courtroom is sometimes equated with the determination of credibility. They, of course, are not the same thing. In a broad sense, credibility is always in issue when a decision is based on evidence presented to the court, whether viva voce or by affidavit, and whether or not it is challenged by cross-examination or the presentation of conflicting evidence. Credibility means simply worthiness of belief. If evidence is credible, it is of such a character that it is capable of being relied on by the trier of fact. When a court purports to rely on any piece of evidence, it in essence is making an assessment that that evidence is worthy of belief. In making that determination the court will rely, depending on the circumstances of each case, on a host of factors including the consistency with other known facts, its rational strength when viewed against common experience, the reputation and means of knowledge of the witness presenting the evidence and the language employed in its presentation, in addition to the performance of the witness in the courtroom. The determination of credibility in this broader sense is also the province of the trial judge. Thus, even where the case is tried on affidavit evidence without any cross-examination, the conclusions of the trial judge are still entitled to deference on appeal, in the absence of identified error. ... And where the issue is as to what inferences are to be drawn from undisputed acts, appellate deference is also accorded ... So also will the Court of Appeal not substitute its view for the trial judge’s view of the opinion of expert witnesses ... unless the assessment is palpably wrong. ...