Ask a rhetorical question. A rhetorical question is a thought-provoking question that you ask the audience but don't expect them to answer out loud. When you ask the question, you want to answer it either within your introduction or a short time later in your talk. Otherwise, the question serves only to confuse people.
Here's an example for a talk on customer focus-group findings: "If you were a customer doing business with your company, what would most frustrate you in this effort? As I share my findings from the customer focus groups, I'm going to tell you what these frustrations are and what you can do to address them to increase the quality of the service you provide."