A grand jury consists of nine members. Six of these nine members must vote in favor of indictment in order for an individual to be indicted.
A majority (12).
6
All twelve.
12 minimum
There are a variety of numbers when it comes to amount of jurors needed for a case to go to trial in Canada. The minimum number of jurors however is ten or a case won't continue.
Grand Jurors do NOT decide if "a trial is justified." They only rule on indictments. By a simple majority they make the decision that probable cause does or does not exist that the defendant should be charged.
5 jurors
Grand Juries do not decide on whether a trial is needed, or not. They only agree (by a simple majority) that enough probable cause exists to indict you for the offense with which you are charged.
12
twelve
It must be agreed by all (12) of the jurors deciding the case.
All 12.