Probability

Chance Experiments & Variation

1

Record Your Coin Flips (20 Flips)

Flip a coin 20 times. Record each result in the tally chart.

ItemTallyTotal
Heads
Tails
2

Record Your Coin Flips (30 Flips)

Flip a coin 30 times. Record each result.

ItemTallyTotal
Heads
Tails
3

Expected vs Actual – Coins (Set A)

Think about what you expect and what actually happens.

If you flip a coin 20 times, you expect roughly:

10 heads, 10 tails
20 heads, 0 tails
15 heads, 5 tails

If you got 12 heads and 8 tails, that is:

Impossible
Close to expected
Very unusual

If you repeat the experiment, will you get exactly the same results?

Yes, always
Probably not — there is variation
Yes, if I flip the same way
4

Expected vs Actual – Coins (Set B)

Circle the correct answer.

Getting 20 heads in a row is:

Expected
Very unlikely
Impossible

Getting 11 heads out of 20 flips is:

Normal variation
Very unusual
Impossible

The more times you flip, the closer to 50/50 you get. This is:

A coincidence
The law of large numbers
Not true
5

Dice Rolling Experiment (30 Rolls)

Roll a dice 30 times. Record each number.

ItemTallyTotal
1
2
3
4
5
6
6

Dice Rolling Experiment (50 Rolls)

Roll a dice 50 times. Record each number.

ItemTallyTotal
1
2
3
4
5
6
7

Understanding Dice Variation (Set A)

Answer about your dice experiment.

If you roll a dice 30 times, each number should appear about:

5 times
10 times
30 times

Will every number appear exactly 5 times?

Yes, always
Usually not — results vary
Only with a fair dice

If you did the experiment again, the results would be:

Exactly the same
Slightly different
Completely opposite
8

Understanding Dice Variation (Set B)

Circle the correct answer.

Rolling a 6 ten times in a row means the dice is:

Definitely unfair
Could be unfair or just lucky
Definitely fair

If you roll 50 times vs 10 times, results will be:

Less even with 50
More even with 50
Exactly the same

Every roll of a fair dice is:

Affected by the last roll
Independent of the last roll
Always the same
9

True or False? (Chance Experiments)

Circle TRUE or FALSE.

More trials give results closer to expected

TRUE
FALSE

If you flip 3 heads in a row, tails is 'due'

TRUE
FALSE

Variation is natural in chance experiments

TRUE
FALSE

A fair dice always gives equal results

TRUE
FALSE
10

Spinner Experiment – 3 Colours (30 Spins)

Spin a 3-colour spinner (equal sections) 30 times. Record each result.

ItemTallyTotal
Red
Blue
Green
11

Spinner Experiment – 4 Colours (40 Spins)

Spin a 4-colour spinner (equal sections) 40 times. Record results.

ItemTallyTotal
Red
Blue
Green
Yellow
12

Expected vs Actual – Spinner (Set A)

A spinner has 3 equal sections. You spin 30 times.

You expect each colour about:

5 times
10 times
30 times

Getting Red 12, Blue 9, Green 9 is:

Exactly expected
Close to expected
Very unusual

Getting Red 25, Blue 3, Green 2 would be:

Normal variation
Very unusual
Impossible
13

Expected vs Actual – Spinner (Set B)

A spinner has 4 equal sections. You spin 40 times.

You expect each colour about:

10 times
20 times
5 times

Getting 11, 9, 10, 10 is:

Close to expected
Very unusual
Impossible

If one colour appeared 25 times out of 40, that suggests:

Normal variation
The spinner may not be fair
Nothing unusual
14

True or False? (Chance Experiments – Set B)

Circle TRUE or FALSE.

If you roll a dice 6 times, each number will appear exactly once

TRUE
FALSE

Variation means results differ from trial to trial

TRUE
FALSE

More trials make results closer to expected values

TRUE
FALSE

If a coin lands on heads 5 times, tails must come next

TRUE
FALSE
15

True or False? (Chance Experiments – Set C)

Circle TRUE or FALSE.

A fair spinner with 4 equal sections gives each section a 1 in 4 chance

TRUE
FALSE

Repeating an experiment always gives the same results

TRUE
FALSE

If you flip a coin 100 times, results will be closer to 50/50 than with 10 flips

TRUE
FALSE

Rolling a dice 12 times guarantees each number appears twice

TRUE
FALSE
16

Match Experiment to Expected Outcome

Draw a line from each experiment to the expected result.

Flip coin 20 times
Roll dice 30 times
Spin 3-colour spinner 30 times
Spin 4-colour spinner 40 times
Each number about 5 times
About 10 heads, 10 tails
Each colour about 10 times
Each colour about 10 times
17

Match Term to Meaning

Draw a line from each term to its definition.

Variation
Trial
Fair
Expected outcome
What we predict should happen
Each attempt in an experiment
Differences between results each time
Every outcome is equally likely
18

Coin Flip Totals (Set A)

Heads + Tails = Total flips. Find the missing number.

20
11
?
20
?
8
30
17
?
30
?
14
50
23
?
19

Coin Flip Totals (Set B)

Find the missing number.

40
22
?
40
?
19
50
?
28
100
47
?
100
?
52
20

Dice Experiment Totals

The 6 dice outcomes must add up to the total rolls. Find the missing number.

30
25
?
30
?
7
60
49
?
60
?
12
21

Expected or Surprising Results?

Sort each outcome: is it expected or surprising?

Coin: 11 heads out of 20
Coin: 19 heads out of 20
Dice: each number 4-6 times out of 30
Dice: number 3 appears 15 times out of 30
Spinner (3 sections): 9, 11, 10 out of 30
Spinner (3 sections): 2, 3, 25 out of 30
Expected (normal variation)
Surprising (unusual)
22

More or Fewer Trials?

Sort each statement about trials.

More trials give more reliable results
10 coin flips always give exactly 5 heads
100 rolls of a dice are more even than 6 rolls
Fewer trials make results perfectly predictable
Variation decreases with more trials
Every experiment gives exactly the expected result
True
False
23

Coin Flip Results – Picture Graph (Set A)

These are results from 20 coin flips. Answer the questions.

Heads
Tails
1

How many more heads than tails?

2

Is this close to the expected result of 10/10?

3

Would you say this coin is probably fair? Why?

24

Coin Flip Results – Picture Graph (Set B)

These are results from 30 coin flips.

Heads
Tails
1

How many total flips?

2

How close to 15/15 was this result?

3

Would doing 100 flips likely give a result closer to 50/50?

25

Dice Rolling Results – Picture Graph

These are results from 30 dice rolls.

1
2
3
4
5
6
1

Which number appeared most often?

2

Which appeared least often?

3

Each number was expected about 5 times. Were results close?

4

Does this suggest the dice is fair? Why?

26

Record and Reflect – Marble Draws

Put 3 red and 2 blue counters in a bag. Draw one, record the colour, replace it. Repeat 20 times.

Red was drawn ___ times. Blue was drawn ___ times.

You expected red about ___ times and blue about ___ times. Were you close?

Why might your results not be exactly 12 red and 8 blue?

27

Predicting from Experiments (Set A)

Use experimental results to predict.

Spinner has 2 red sections and 1 blue. After 30 spins, you expect red about:

10 times
20 times
30 times

After 60 spins of the same spinner, red should appear about:

20 times
40 times
60 times

You got 22 red out of 30. This is:

Close to expected
Exactly expected
Very far from expected
28

Predicting from Experiments (Set B)

Circle the best prediction.

A bag has 1 red and 3 blue. In 20 draws (with replacement), you expect red:

About 5 times
About 10 times
About 15 times

You drew red 7 times out of 20 from a 1-red-3-blue bag. This is:

Close to expected
Very unusual
Impossible

With more draws, results should get:

Closer to expected
Further from expected
Exactly the same
29

Describe Your Coin Flip Results

Write about what happened in your coin flip experiment.

How many heads? How many tails? How close to 10/10?

Was your result exactly what you expected? Why or why not?

If you did it again, would you expect the same result? Explain.

30

Describe Your Dice Results

Write about your dice experiment.

Which number came up the most? The least?

Were all numbers rolled about the same number of times?

Why do we get different results each time even though the dice is fair?

31

Compare Two Experiments

Compare results from different experiments.

Compare your 20-flip results with your 30-flip results. Which was closer to 50/50?

Compare your 30-roll results with your 50-roll results. Which was more even?

What does this tell you about the number of trials?

32

Spinner Experiment Reflection

Make a spinner with 3 equal sections (red, blue, green). Spin 30 times.

Record your results: Red = ___, Blue = ___, Green = ___

Each colour should appear about ___ times. Were your results close?

What if the spinner had 2 sections red and 1 blue? What would you expect?

33

Unequal Spinner Experiment

Make a spinner with 2 equal red sections and 1 blue section. Spin 30 times.

Record: Red = ___, Blue = ___

You expected red about 20 times and blue about 10 times. How close were you?

Why did red come up more often?

34

Predicting from Experiments (Set C)

Use experimental data to make predictions.

You flipped 14 heads out of 20. You predict heads is:

Impossible
Less likely than tails
More common but close to even

You rolled a 6 eight times out of 30. You expect 6 to appear:

Never again
About 1/6 of the time
Every time

A spinner landed on red 18 times out of 30. Red section is probably:

Smaller than others
About equal to others
Larger than others
35

Class Comparison

Answer these questions about comparing experiments.

If every student in your class flipped a coin 20 times, would everyone get the same result?

If you added up ALL the class's heads and tails, would it be close to 50/50? Why?

36

Class Comparison (Set B)

Answer about comparing class experiments.

If 5 students each roll a dice 30 times, will they all get the same most-common number? Why or why not?

If we combine all 150 rolls (5 × 30), would the results be more even? Why?

What does this tell us about sample size?

37

Drawing Conclusions from Experiments

Answer each question about experimental results.

You rolled a dice 60 times: 1=9, 2=11, 3=10, 4=10, 5=8, 6=12. Is the dice fair? Why?

A friend got 1=3, 2=2, 3=1, 4=0, 5=2, 6=2 in only 10 rolls. Is the dice fair? Can you tell from 10 rolls?

38

Match Experiment to Conclusion

Draw a line from each experiment to its best conclusion.

Coin: 48 heads out of 100 flips
Dice: number 6 appeared 15 times out of 30
Spinner (2 sections): Red 22, Blue 8 out of 30
Coin: 3 heads out of 10 flips
Too few trials to draw a firm conclusion
Close to expected — coin seems fair
Red section is probably larger than blue
Appeared more than expected — could be unfair
39

Design Your Own Experiment

Design a chance experiment.

What will you test? (coin, dice, spinner, cards?)

How many trials will you do?

What do you predict will happen?

Record your results:

Were your results close to your prediction? Describe the variation.

40

Challenge: Fair or Unfair?

Think about fairness in chance experiments.

You roll a dice 60 times and get: 1 = 8, 2 = 11, 3 = 10, 4 = 9, 5 = 12, 6 = 10. Is the dice fair? Explain.

How many times would you need to roll to be more confident about whether it is fair?

How could you test if a coin is fair?

41

Home Activity: More Chance Experiments

Try more chance experiments at home!

  • 1Spin a spinner (or make one from a paper plate) 30 times. Record and compare to expected.
  • 2Put 3 red and 2 blue counters in a bag. Draw one 20 times (replace each time). Is red picked more?
  • 3Flip 2 coins at once, 20 times. How often do you get 2 heads? Is it what you expected?
  • 4Compare your results with a family member. Did you get the same? Discuss why or why not.
42

Dice Roll Experiment (60 Rolls)

Roll a dice 60 times and tally the results.

ItemTallyTotal
Rolled a 1
Rolled a 2
Rolled a 3
Rolled a 4
Rolled a 5
Rolled a 6
43

Experimental vs Theoretical Probability

Compare what you expect to what actually happens.

Theoretical probability of each number on a dice = ___. For 60 rolls, expected frequency of each = ___

Look at a set of 60 dice rolls. Were any numbers very different from expected? Which ones?

If you rolled 600 times instead of 60, would you expect the results to be closer to theoretical? Why?

44

Variation in Chance Experiments (Set A)

Circle the correct answer.

You flip a coin 10 times and get 8 heads. This means:

The coin is unfair
This can happen by chance
Tails will come up 8 times next

You repeat an experiment and get different results. This is called:

An error
Variation
A mistake

To get results closer to theoretical probability, you should:

Use fewer trials
Use more trials
Change the experiment

Experimental probability of heads after 100 flips: 53 heads. This is:

Very unusual
Normal variation
Proof the coin is biased
45

Planning a Chance Experiment

Plan a complete chance experiment.

What will I test? (coin, dice, spinner, cards?)

How many trials will I do?

What is the theoretical probability of my target outcome?

What do I predict will happen?

46

Record and Analyse Experiment Results

Record the results of your experiment and compare to predictions.

Record your results (tally or list):

Experimental probability of your target outcome = ___/___

Theoretical probability = ___. Are they close?

Describe the variation in your results.

47

Spinner Results (Scale: 1 icon = 2 spins)

A spinner has 3 equal sections: Red, Blue, Green. After 60 spins:

Red
Blue
Green
1

How many times did each colour appear?

2

Theoretical probability of each colour = 1/3. Expected frequency for 60 spins = ___

3

Which result was furthest from the expected frequency?

4

Would repeating the experiment 600 times give results closer to 1/3 each?

48

Simulating Real Events

Use a chance experiment to simulate a real situation.

A weather forecast says there is a 50% chance of rain each day this week. Use a coin flip to simulate rain (heads = rain). Flip the coin 7 times. Record results.

On how many simulated days did it rain?

Run the simulation 3 times. Do you always get the same answer? What does this tell you?

49

Analysing a Long-Run Frequency

Investigate how results change as the number of trials increases.

Flip a coin 10 times. Record proportion of heads: ___/10 = ___

Flip it another 10 times (total 20). New proportion: ___/20 = ___

Flip 30 more (total 50). Proportion: ___/50 = ___

What do you notice about the proportion as trials increase?

50

Sort: Natural Variation or Unfair Device?

Decide if each result is likely to be natural variation or evidence of an unfair device.

48 heads in 100 coin flips
90 heads in 100 coin flips
12 sixes in 60 dice rolls
35 sixes in 60 dice rolls
18 reds in 60 spinner spins (3 equal sections)
50 reds in 60 spins (3 equal sections)
Natural variation
Likely unfair
51

Compare Two Experiments

Two students run the same coin-flip experiment.

Student A: 20 flips, 13 heads. Student B: 20 flips, 9 heads. Are these results surprising? Why?

If they combined results: 22 heads in 40 flips. Proportion = ___. Is this closer to 1/2?

Why do two students doing the same experiment get different results?

52

Challenge: Is This Dice Fair?

Analyse this dice roll data to determine if the dice is fair.

Results from 120 rolls: 1=18, 2=20, 3=19, 4=22, 5=21, 6=20. Expected frequency of each number = ___. Are these results within normal variation?

Now consider: 1=5, 2=7, 3=6, 4=8, 5=89, 6=5. Is this dice likely fair? Explain.

How many trials would you need to be more confident that a dice is fair?

53

Probability Summary and Reflection

Reflect on everything you have learned about probability.

Write three things you know about probability and chance experiments.

What is the most important thing to remember about the difference between theoretical and experimental probability?

Give a real-life situation where understanding probability would be helpful.