 We'll have only some of the information. We'll never be able to know the answers. And let me just cut to the punchline, because some of you spend the whole course expecting that I'm going to say something different. You're expecting that I say, with this magic formula, you can get something out of nothing. You can make certainty out of uncertainty. Ah, you can't. Without all the information, you will never know the answer. But still, maybe you can do something reasonable in the real world with the information that you have. Statistics is the science of making decisions under uncertainty. That uncertainty bit is really important. The making decisions bit is also crucial. We're not in the business of knowing stuff here. Contrary to popular belief, we are in the business of making reasonable real world actions with the information that we have available. You give up on knowing. That's okay. Maybe we can still do something useful. Make a good decision out of it.