After you have reported for jury duty, you will be selected for a jury panel along with other jurors. The jury panel is sent to the courtroom which is trying a case. A jury of six people will be selected in the courtroom. The judge in the courtroom will explain the case and introduce the lawyers and other participants. As part of jury selection, the judge and the lawyers will then question the jury panel members to determine if anyone has knowledge of the case, a personal interest in it, or any feelings that might make it hard to be impartial. This process is called "voir dire", a phrase meaning "to speak the truth".
Questions asked during voir dire may seem personal but should be answered completely and honestly. The questions are not intended to embarrass anyone but are used to make sure that members of the jury do not have opinions or past experiences which might prevent reaching an impartial decision.
During voir dire the lawyers may ask the judge to excuse a juror from sitting on the case. This is called "challenging a juror". There are two types of challenges: a challenge for cause and a peremptory challenge.
A challenge for cause means the lawyer has a specific reason for thinking that a juror would not be able to be impartial. For example, the case may involve driving under the influence of alcohol. If a juror had been in an accident with a drunk driver and was still upset about it, the defense attorney could ask that the juror be excused for that reason. There is no limit to the number of jurors who may be excused for challenge for cause.
Peremptory challenges do not require the lawyers to state any reason for excusing a juror.
Peremptory challenges are intended to allow lawyers, both prosecution and defense, to do their best to assure that the trial is fair. Peremptory challenges are limited to three per side in most cases.