What is the test for establishing inherent improbability in a witness statement?

"To warrant the rejection by a reviewing court of statements given by a witness who has been believed by the trial court or the jury, there must exist either a physical impossibility that they are true, or it must be such as to shock the moral sense of the court; it must be inherently improbable and such inherent improbability must plainly appear." (People v. Ozene (1972) 27 Cal.App.3d 905, 910, disapproved on another point in People v. Gainer (1977) 19 Cal.3d 835, 844, 851-852.) "Contradictions and inconsistencies alone will not necessarily constitute inherent improbability." (People v. Swanson (1962) 204 Cal.App.2d 169, 172.)