Lesson · Grade 7 · Mathematics
Experimental probability from a set of trials
- Grade 7
- Mathematics
- 1 min 16 s
- British Columbia
- BC7-MA-70
Two coins are flipped 20 times and every result is recorded; two heads came up 6 times, so the experimental probability is 6/20 = 3/10 = 30%. The video shows that experimental probability is the number of times an event happened divided by the number of trials, and that each group of 10 trials had two heads 3 times.
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In one sentence
The question this lesson answers
If we flip two coins, how likely are two heads? Let us find out with real trials.
One coin cannot change how the other one lands, so these are independent events.
Transcript
What the lesson says
If we flip two coins, how likely are two heads? Let us find out with real trials.
One coin cannot change how the other one lands, so these are independent events.
We flip both coins together 20 times, and write down every result.
Each flip of the two coins is one trial, so we have 20 trials.
Now find every trial where both coins landed on heads.
Two heads came up 6 times.
Experimental probability is the number of times it happened, divided by the number of trials.
So the experimental probability of two heads is 6 out of 20.
Divide the top and the bottom by 2, to get three tenths.
Three tenths is the same as 30 percent.
Look: each group of 10 trials had two heads 3 times.
So experimental probability comes from real trials: the times it happened, divided by the number of trials.
Curriculum
Where this fits
- British Columbia, Grade 7
Mathematics, Data and probability: experimental probability with two independent eventsBC7-MA-70
Previous: All the Outcomes of Two Spins: Tables and Tree DiagramsNext: Why More Trials Give a Better Estimate
The outcomes and strands follow the British Columbia curriculum.
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