On a rainy evening you return to your ground-floor apartment and discover that you have been burglarized. You can’t believe it, because you are certain you locked the door when you went out. You share the apartment with a roommate.

For each of the following situations, invent at least three hypotheses aimed at explaining what went wrong or at solving the problem. Then, for each hypothesis, describe one or more experiments or inquiries that would confirm or disconfirm the hypothesis.