Weight control is a serious issue for packaging of food stuffs. If more than 30% of a production run are under filled then the production run must be redone. A single production run makes 600 packages (the population). A quality control inspector at a large food packaging plant simply just selects the first 50 packages produced that day to weigh and finds 12 of them are under filled. What assumption did the inspector violate that will stop them from doing a hypothesis test