A petit juror listens to the evidence of a case and, along with other members of the petit jury, determines its validity, according to the New Jersey Judiciary. Depending on the state and the type of trial, the size of petit juries vary in size, commonly six or 12 jurors.
In a criminal trial, a petit jury has to decide whether the defendant is guilty of committing the act with which he is charged, explains the New Jersey Judiciary. In a civil case, the petit jury determines if the plaintiff wins the case. When potential petit jurors are summoned for jury duty, they must present themselves at the assigned court and wait to be called by a judge for voir doire, a process in which a judge questions potential jurors before selection. If a potential petit juror is selected, he must report at the time required to begin serving on the petit jury along with his fellow jurors.
A petit jury is a common law type of jury that is so named to distinguish it from a grand jury in criminal justice proceedings, according to the Rutherford County, Tennessee, Circuit Court Clerk's office. A grand jury is a larger group, hence the name, commonly consisting of 16 to 23 jurors, and it decides whether a suspect is to be legally charged with a crime.