Handling Data 5
3 marks · EasyThe table shows the probability that a spinner will land on each colour.
| Colour | Probability |
|---|---|
| Red | 0.3 |
| Green | 0.5 |
| Blue | p |
a) Write down the value of .
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
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0.2 (±0.01)
Common mistakes: Adding instead of subtracting; Writing 1.0 or -0.2
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Marking points
M1 · 1 mark · States or uses the rule that the sum of all probabilities is 1.
M2 · 1 mark · Substitutes known probabilities correctly into the rule: 0.3 + 0.5 + p = 1 or 0.3 + 0.5 = 0.8.
A1 · 1 mark · Finds correct value: p = 0.2.
Worked solution
The probability of all possible spinner outcomes must add up to 1.
Add the given probabilities together:
So, p = 1 - 0.8 = 0.2