Probability Line

Probability is the chance that something will happen. It can be shown on a line.

We can say that the probability of an event occurring will be somewhere between impossible and certain.

As well as words we can use fractions or decimals to show the probability of something happening. Impossible is zero and certain is one. A fraction probability line is shown below.

We can show on our line the chance that something will happen:

a) The sun will rise tomorrow.
b) I will not have to learn maths at school.
c) If I flip a coin it will land heads up.
d) If you have a choice of red, yellow, blue or green you will choose red.

Between 0 and 1

Note:

• The probability of an event will not be less than 0.
  This is because 0 is impossible (sure that something will not happen).
• The probability of an event will not be more than 1.
  This is because 1 is certain that something will happen.