Final answer:
The standard used to determine guilt or innocence in a criminal trial is beyond a reasonable doubt, which is higher than the other standards such as preponderance of the evidence or clear and convincing evidence, and is unrelated to probable cause, which is about lawful search and arrest.
Step-by-step explanation:
The standard used to determine the guilt or innocence of a person criminally charged is beyond a reasonable doubt. This is the highest burden of proof in the American legal system and is required due to the potentially severe consequences that a criminal conviction can entail, including the loss of liberty or even life. When a jury deliberates in a criminal trial, they must come to a conclusion that there is no reasonable doubt in the minds of jurors that the defendant committed the crime.
Preponderance of the evidence is the standard used in civil cases, where the plaintiff must show that the evidence is more likely than not in their favor. Clear and convincing evidence is a higher standard than preponderance, but lower than beyond a reasonable doubt, often used in certain civil cases and some aspects of criminal proceedings. Probable cause is not a standard for determining guilt or innocence, but rather a requirement for police to have before conducting a search or making an arrest.