Sign test

A sign test is kind of like playing a game where you want to see if something is different or the same. You might be playing a game where you and your friend each have a bag of 10 marbles. Your bag has some red marbles and some blue marbles, and your friend's bag has the same amount of red and blue marbles.

You want to see if your bag has more red marbles than your friend's bag. To do that, you would take out one marble at a time from both bags, and every time your marble is red and your friend's marble is blue, you put a point on your side. Every time your marble is blue and your friend's is red, you put a point on your friend's side. Every time both marbles are the same color, you don't put a point for anyone.

At the end, you count up the points on each side. If you have more points on your side, that means you have more red marbles in your bag than your friend's bag. If your friend has more points, that means they have more red marbles in their bag.

This game is kind of like a sign test, where you compare two groups (like your bag and your friend's bag) to see if they're different in some way. Instead of marbles, you might be comparing two sets of numbers, or two types of treatments, or any other two things you're interested in. The sign test just helps you figure out if there's a difference between them, and how big that difference might be.