Y9 Booster

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Y9 Booster

• Lesson 11

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Objectives what you should be able to do by the
end of the lesson

• Systematically record all the outcomes of an
  experiment
• Understand that increasing the number of times an
  experiment is repeated generally leads to better
  estimates of probability
• Understand the links between experimental and
  theoretical probabilities

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Here are some terms to with probability
Outcome Sample space Equally likely Mutually
exclusive Relative frequency Fair likelihood
Working in groups agree the meaning of the
term(s) and think how you could explain the
meaning to others.
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Outcome When tossing a coin there are two
possible outcomes heads or tails. When
throwing a die there are 6 possible outcomes.
t
x x x x x x x x x x x x
Sample space A sample space is a table or grid
showing all the possible outcomes of an
experiment.
h
1 2 3 4 5 6
Equally likely If you choose a card from a pack
of 52 the events diamond, heart, club or spade
are equally likely.
Mutually exclusive events that cannot both
occur in one experiment. e.g. throwing a 3 and a
5 with one roll of a dice.
Relative frequency the experimental probability
of an outcome.
Fair a fair dice is one that is not weighted
towards a particular outcome or outcomes. All
the outcomes are equally likely.
Likelihood The chance of something happening in
an experiment. An outcome may be likely, very
likely, not likely, impossible or certain.
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Pairs game M11.1a
A childs game has two windows.
In each window, one of three different animals a bird, cat or dog is equally likely to appear.
When both windows show the same animal, the child shouts snap (this counts as a success).
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Pairs game M11.1b

• Estimate the probability of getting a snap,
  like this.
• Cut out the three animal cards, place them face
  down and shuffle them.
• Pick a card. This represents the animal that
  appears in window 1.
• Replace the card, face down. Shuffle the cards
  again.
• Pick a card. This represents the animal that
  appears in window 2.
• Decide how to record this result.
• Decide how many times you are going to repeat
  this process.
• Use your results to work out the probability of
  getting two animals the same.

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How many times did you repeat the experiment?
How many snaps did you record?
What is the experimental probability of a snap?
Which is most likely a snap or not a snap?
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What are the possible outcomes in the pairs game?
bb, bc, bd, cb, cc, cd, db, dc, dd,
window 2
OR
b c d
b bb bc bd
c cb cc cd
d db dc dd
window 1
Using the list of outcomes what is the
theoretical probability of winning?
What is the theoretical probability of getting a
cat and a dog?
What is the theoretical probability of not
getting a bird?
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How does your experimental probability compare
with the theoretical one? Are they the same? If
not, why do they differ?
How can you improve your estimate?
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Objectives how have we done?

• Systematically record all the outcomes of an
  experiment
• Understand that increasing the number of times an
  experiment is repeated generally leads to better
  estimates of probability
• Understand the links between experimental and
  theoretical probabilities

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Thank you for your attention