How do scientists tell a real pattern from chance?

You flip a coin five times and it comes up heads every single time. Wild luck? A trick coin? Or just… Tuesday? Scientists face this question constantly: when something weird happens, how do they know if it's a real signal hiding in the noise, or just the universe being randomly weird for no reason at all?
Here's the thing about randomness: it's supposed to look weird sometimes. If you flip a fair coin a thousand times, you'll definitely see streaks of five heads in a row. You'll see patterns that feel meaningful. That's just what random does when you give it enough chances. The trick is figuring out: is this pattern weirder than random should be?
