Final answer:
The guideline being used is the Guideline for summarizing key points.
Step-by-step explanation:
The guideline for informative presentations being used when an instructor gains attention by saying, 'You might see this information again on the exam' is the Guideline for summarizing key points. By highlighting the importance of the information for the exam, the instructor is emphasizing the key points that students should focus on and remember.
This guideline helps the instructor ensure that important information is effectively communicated and retained by the audience.