If a movie theater lists a movie time as 8:00 pm, about time do you expect the movie (after previews/ads) to begin?

If a movie theater lists a movie time as 8:00 pm, about time do you expect the movie (after previews/ads) to begin? Published on January 10, 2018 → Survey conducted on January 10, 2018 on 5234 U.S. adults