What is posterior?

Posterior is what you figure out after looking at some clues or evidence.

Imagine you have a bag full of different kinds of candies, chocolates, gummies, and lollipops. You can’t see inside the bag, but you take out a few pieces one by one. Each time you pull out a candy, it gives you a clue about what might be inside the whole bag. After pulling out several candies, you start to guess: What kind of candy is most common in the bag? That guess, based on the candies you've seen so far, is your posterior.

Think about it like playing a game of "Guess Who?" with your friend. At first, you don’t know who your friend has picked. But as they give you clues, They have glasses, They are wearing a hat, you start to narrow down the possibilities. Each clue helps you make a better guess. That process is just like how posterior works: it’s your best guess after seeing some evidence.

So, posterior means "what we think now", based on what we've seen or learned before.