 So I've used words like belief and best guess. I'd better give you some vocabulary. A hypothesis is a statement of belief about a parameter. It's just a description of how the world might look. It doesn't have to be true. So I might be standing in that clearing and utter some preposterous garbage, like the true average height of all the trees is less than 20 meters. Oh, that happens to be false. I don't know it though because I haven't measured any trees. I'm allowed to have a hypothesis like this. It's just some statement about how the world might work. And we'll see how we'll feel about it after we get some data.