1. Probability Today you will need …… Orange Books Calculator Pen Ruler
Week 6
Today you will need ……
Orange Books
Calculator
Pen
Ruler
Complete your tracking sheet to evaluate your skills before the lesson

2. Diagnostic Results
&
Diagnostic Results
42%

3. What you need to know E3 –L2
Understand that some events are impossible
Understand that some events are certain to happen
Know that some events are more likely to occur than others
Understand the concept of possible outcomes, e.g. there are two possible outcomes for the gender of a baby Understand that some events can happen in more than one way, e.g. there are three possible ways of getting an odd number with the throw of a die
Understand that probability is an expression of likelihood, and use terms such as a one in two chance
Understand that the likelihood of an event is measured on a scale from 0 (impossible) to 1 (certain)
Understand that likelihood (or probability) is expressed as the number of ways the event can happen divided by the total number of possible outcomes
Understand that likelihood or probability can be written as a fraction, decimal or percentage, e.g. the likelihood that a coin will land heads-up is 50%, .5 or 1/2
The expression there is a fifty-fifty chance is an expression of likelihood using percentages
Understand that events are independent when the outcome of one does not influence the outcome of another, e.g. the gender of a baby does not influence the gender of a second one
Understand that events are combined when the outcome depends on the separate outcome of each independent event, e.g. the likelihood that twins will both be girls
Record the range of possible outcomes of combined events in tree diagrams or in tables

4. What will you learn today
What will you learn today? (something you did not know yesterday) By the end of this session I will be able to…
Show that some events are more likely to occur than others
Express the likelihood of an event using fractions, decimals and percentages with the probability scale of 0 to 1
Identify the range of possible outcomes of combined events and record the information using diagrams or tables
Examination style questioning
axis, scale, title, segments, bar, line, pictogram, pie, scatter, prediction, line of best fit
Key Words

5. What’s the difference between chance and probability?
Chance is described in words. Eg. Impossible, Unlikely, Evens, Likely, Certain Probability is given a numerical value. Probability is given as a fraction, decimal or percentage.

6. The rule of probability
𝑯𝒐𝒘 𝒎𝒂𝒏𝒚 𝒘𝒂𝒚𝒔 𝒕𝒉𝒆 𝒐𝒖𝒕𝒄𝒐𝒎𝒆 𝒚𝒐𝒖 𝒘𝒂𝒏𝒕 𝒄𝒂𝒏 𝒉𝒂𝒑𝒑𝒆𝒏 𝑻𝒐𝒕𝒂𝒍 𝒐𝒖𝒕𝒄𝒐𝒎𝒆𝒔
It is often easier to give a probability as a fraction using the rule above. If you are given probabilities in decimals, then use decimals.

7. Here’s how the rule works:
A bag contains 9 blue marbles, 5 red marbles and 6 green marbles. What’s the probability of selecting a blue marble from the bag?
What you want:
How many blue marbles there are 9
Total outcomes:
How many marbles there are in total 20

8. More than one option
A bag contains 6 blue marbles, 5 red marbles and 9 green marbles. What’s the probability of selecting a green or red marble from the bag?
What you want:
How many green or red marbles there are 14
Total outcomes:
How many marbles there are in total 20

9. Dice Probability

10. Spinner probability

11. What is a probability scale?
This is a line where events can be placed to show the chance or probability of an event occurring.
Impossible
Certain
3 4
1 4
1 2 1

12. Combined outcomes 1 4 Suppose I toss two coins: or
I would get one of these combinations:
Heads, Heads Heads, Tails Tails, Heads Tails, Tails
H, H H, T T, H T, T or
What is the probability of getting two heads?
1 4
Only one of these four combinations is two heads

13. Probability outcomes T, T T, H T H, T H, H H Second Coin First Coin
A Sample Space is a list of all the possible outcomes, e.g. HH, HT, TH, TT
T, T
T, H T
H, T
H, H H
Second Coin
First Coin
We can show this in a Sample Space Diagram:
There are 4 possible outcomes if you toss a coin twice
So the probability of two heads is ¼

14. Tree diagrams.
If I roll a dice, what is the probability the result will be even?
3 6
3 ÷ 6 =
0.5
Even
Check the results add up to 1
= 1
Odd
3 6
3 ÷ 6 =
0.5

15. Please don’t write on the worksheets
Individual Study
Choose which areas to develop depending on your own strengths and areas identified from your diagnostic
Computers available
Please don’t write on the worksheets

16. Reflection of the lesson
What did you learn new today?
Why did you learn it?
How are you going to remember it?