ELI5: pearsons coefficient

Pearson's coefficient is a special number between -1 and 1 that tells us how closely two things change together in everyday life.

Imagine you are watching two friends, Timmy and Tommy, on a playground. This number is like a score that shows if they are doing the exact same thing, the exact opposite thing, or ignoring each other completely.

Here is how the score works in normal life:

• The Best Friends Score (Close to +1): This means when one thing goes up, the other thing goes up too. Think about the weather and ice cream sales. When the summer temperature goes up, the number of ice cream cones eaten also goes up. They move in the same direction together.
• The See-Saw Score (Close to -1): This means when one thing goes up, the other thing goes down, just like two kids on a see-saw. Think about your warm winter coat and hot summer days. As the temperature outside goes up, the number of coats worn outside goes down. They move in opposite directions.
• The Stranger Score (Close to 0): This means the two things have nothing to do with each other. Think about the size of your shoe and your score on a spelling test. Having bigger feet does not make you better or worse at spelling. The two things ignore each other, so the score stays near zero.