Step by step
The question
Question: A spinner with 4 equal parts landed on red 18 times in 30 spins.
Predict the reds in 200 spins.
1 Times it happened over times tried
It happened 18 times out of 30 spins.
So the experimental probability is 18/30.
P(red) = 1830
Experimental probability comes from what really happened in the experiment.
experimental = what really happened
18 and 30 can both be divided by 6.
So it is 3/5.
= 18 ÷ 630 ÷ 6 = 35
2 Predict
We expect the same fraction in 200 spins: 3/5 of 200.
Of means times.
= 35 × 200
200 divided by 5 is 40.
200 ÷ 5 = 40
Then times 3.
= 3 × 40
So about 120.
= ≈ 120
Careful!
A prediction is only about how many.
The next spins can come out a bit different.
Careful: about, not exactly: chance can change it
3 Check
Let's check: 120 out of 200 is 3/5, the same fraction as before.
So the answer is right!
120200 = 35
Let's look back.
First: times it happened over times tried.
Then: predict.
Last: check.
Answer
Careful: about, not exactly: chance can change it