I'm not sure how much the rules vary, but in our case there were 18 candidate jurors and both sides were allowed to dismiss 3 without cause or justification. Additionally, if either side could argue there was a cause, additional jurors could be dismissed (requiring new jurors to be summoned), but that didn't happen. The plaintiffs removed the 3 with any college at all.
That could be a representative sample of the area the trial was held in. Trial by jury of your peers means that some juries will be composed of mostly and sometimes even all "peers" with less formal education that most would think appropriate for the subject matter being discussed.