There are two types of juries: petit (or trial) juries and grand juries.
Petit Jury
A trial jury, also known as a petit jury, decides whether the defendant committed the crime as charged in a criminal case, or whether the defendant injured the plaintiff in a civil case.
Petit juries consist of 6-12 people.
Petit juries may hear civil or criminal cases.
Trials are generally public, but jury deliberations are private.
Defendants have the right to appear, testify, and call witnesses on their behalf.
The final outcome is a verdict, in favor of plaintiff or defendant in a civil case, or guilty/not guilty in a criminal case.
Grand Jury
A grand jury is presented with evidence from the U.S. attorney, the prosecutor in federal criminal cases. The grand jury determines whether there is “probable cause” to believe the individual has committed a crime and should be put on trial. If the grand jury determines there is enough evidence, an indictment will be issued against the defendant.
Grand juries consist of 23 people.
Grand jury proceedings are not open to the public.
Defendants and their attorneys do not have the right to appear before the grand jury.