Lesson

Can you list all the outcomes from an experiment? Can you count how many match a description?

Sally rolls a twelve-sided die and writes down whether she rolls 6 or more. If she does, she writes "yes", otherwise she writes "no".

Which of the following is the list of outcomes where she writes "yes"?

A

2,\ 4, \ 6, \ 8, \ 10, \ 12

B

1, \ 2, \ 3, \ 4, \ 5, \ 6

C

6, \ 7, \ 8, \ 9, \ 10, \ 11, \ 12

Worked Solution

Idea summary

The outcomes for an experiment are the possible results that could happen.

This video looks at how to find the probability for an event as a fraction.

A six-sided dice is rolled.

a

What is the probability of rolling a four?

Worked Solution

b

What is the probability of rolling an odd number?

Worked Solution

Idea summary

We can write the probability of an event as a fraction using the formula \text{Probability} = \dfrac{\text{Number of what we want to happen}}{\text{Total number of outcomes}}

This video looks at finding the probability of an event from a spinner.

Look at this spinner:

a

Complete the table, showing the probability of each outcome.

Worked Solution

b

What is the sum of the probabilities for each outcome?

Worked Solution

Idea summary

The probability of something happening can be written as a fraction. If there are 3 of what we want, out of a total of 10, then we have 3 chances out of 10 of it happening. As a fraction, it's \dfrac{3}{10}.