October 15, 2012, Written by Jeremy Peters, New York Times – The format for the second presidential debate is designed to be a little less stiff — a free-flowing question-and-answer session between the candidates and a studio audience. But behind the scenes, little is left to chance. There are 80 participants, culled by Gallup, the polling firm, from a sample of uncommitted voters who live near the debate’s location in Hempstead on Long Island. On Tuesday morning, they are scheduled to arrive at the site to begin rehearsals with the moderator, CNN’s Candy Crowley. They will have prepared questions to ask but will not use them during the prep session. To preserve as much secrecy as possible, they will rehearse with dummy questions. Ms. Crowley will select the participants to call on during the actual debate, which she will determine by reviewing their questions beforehand. The campaigns are not allowed to screen any of them.