Understand the Probability Scale

Probability is all about the chance of something happening.

One thing you will be expected to do is to say which of two events is more or less likely.

To do this, we use the probability scale:

There's a couple of things to notice here.

The scale starts at impossible on the left and gets more likely until we hit certain on the right.

The probability scale starts at 0 (impossible) and ends at 1 (certain)

We'll focus on the numbers later - let's just look at words today.

Examples: On the probability scale above, where would you place the following events?

1) You throw a coin and get a head.

Answer: This is an even chance, so it would go at point D.

2) You roll a dice and get a 6.

Answer: This is very unlikely, so it would go at point B.

Let's move on to some questions now.