Experimental probability from real trials
Roll a die 60 times and the results almost never split perfectly evenly — experimental probability is about what actually happens, not just what should.
Part of your national curriculum
- Probability: Record, describe and analyse the frequency of outcomes of simple probability experiments involving randomness, fairness, equally and unequally likely outcomes
Lesson overview
What you'll learn in this lesson
Record, describe and analyse the frequency of outcomes of simple probability experiments involving randomness, fairness, equally and unequally likely outcomes
Key learning points
- • Relative frequency
- • Worked example
- • Fair vs unequally likely
This lesson at a glance
- 23 minutes
- 17 parts to scroll through
- 3 quick checks
- Marked quiz at the end
- Gentle pace: short sittings with pauses
Words to know
Scroll down — the lesson carries on below
Watch & discover
Part 1 of 17
Visual introductionPicture this
Experimental probability from real trials
Roll a die 60 times and the results almost never split perfectly evenly — experimental probability is about what actually happens, not just what should.
In a nutshell
Record, describe and analyse the frequency of outcomes of simple probability experiments involving randomness, fairness, equally and unequally likely outcomes
Learning cycle
Part 2 of 17
Learning cycle 1 of 2
Part 1 · Relative frequency
A short piece of teaching, then a check to make sure it has landed.
Explore the idea
Part 3 of 17
Learn
Relative frequency
Experimental (or relative) probability = number of successful trials ÷ total number of trials. The more trials you run, the closer this usually gets to the true probability.
Reset break
Part 4 of 17
Pause
That's sitting 1 of 4 done
Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Explore the idea
Part 5 of 17
Learn
Worked example
A coin is flipped 40 times and lands heads 18 times. The experimental probability of heads = 18/40 = 0.45, compared with the theoretical 0.5.
Quick check
Part 6 of 17
Quick check
A coin is flipped 40 times, landing heads 18 times. What is the experimental probability of heads?
Quick check
Part 7 of 17
Reset break
Part 8 of 17
Pause
That's sitting 2 of 4 done
Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Learning cycle
Part 9 of 17
Learning cycle 2 of 2
Part 2 · Fair vs unequally likely
A short piece of teaching, then a check to make sure it has landed.
Explore the idea
Part 10 of 17
Learn
Fair vs unequally likely
A fair die gives each of its six outcomes equal probability, 1/6 each. A biased spinner might give unequal probabilities, e.g. red twice as likely as blue, which experiments can reveal by counting frequencies.
Quick check
Part 11 of 17
Reset break
Part 12 of 17
Pause
That's sitting 3 of 4 done
Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Challenge round
Part 13 of 17
Game · Sort it
Which of these are true?
Drag each card into the right column. Tap a card first if dragging is fiddly.
True
Not true
Challenge round
Part 14 of 17
Game · Fill the gaps
Finish the sentences
Choose the word that belongs in each gap.
Experimental (or relative) ____ = number of successful trials ÷ total number of trials.
A fair die gives each of its six ____ equal probability, 1/6 each.
Challenge round
Part 15 of 17
Game · Recall cards
A coin is flipped 40 times, landing heads 18 times. What is the experimental probability of heads?
Card 1 of 3
Mastery quiz
Part 16 of 17
Marked quiz
End of lesson quiz: Experimental probability from real trials
3 questions, marked with the reasoning shown. No timer.
1. A coin is flipped 40 times, landing heads 18 times. What is the experimental probability of heads?
2. What happens to experimental probability as more trials are run?
3. What is true of a fair six-sided die?
Lesson round-up
Part 17 of 17
Lesson round-up
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Record, describe and analyse the frequency of outcomes of simple probability experiments involving randomness, fairness, equally and unequally likely outcomes