Foundation June 2022 Paper 3 Q20
20 Adam and Bianca each throw the same biased coin.
Here is some information about their throws.
| Number of throws | Number of Heads | |
|---|---|---|
| Adam | 40 | 14 |
| Bianca | 60 | 20 |
Bianca says,
“My results give a better estimate of the probability of Heads than Adam’s results.”
Is she correct?
Tick a box.
- Yes
- No
Give a reason for your answer. [1 mark]
| Answer | Mark | Comments |
|---|---|---|
| Ticks Yes and valid reason | B1 | eg ticks Yes and she has thrown more often |
Additional guidance
| Ignore incorrect or irrelevant statements alongside correct statements, unless contradictory | |
| Ticks No | B0 |
| Ticks Yes and 60 is more than 40 | B1 |
| Ticks Yes and 60 is 20 more than 40 | B1 |
| Ticks Yes and 60 is 10 more than 40 (ignore incorrect value 10) | B1 |
| Ticks Yes and she has more data to look at | B1 |
| Ticks Yes and her number of throws is higher | B1 |
| Ticks Yes and Bianca used more throws which gives her a higher chance of getting heads | B1 |
| Ticks Yes and Adam has less number of throws and has more heads (ignore irrelevant has more heads) | B1 |
| Ticks Yes and Bianca throws more coins | B1 |
| Ticks Yes and she threw it 60 times, Adam only 40 | B1 |
| Ticks Yes and she threw it 60 times, Adam 40 | B0 |
| Ticks Yes and she threw it 60 times and got 20 | B0 |
| Ticks Yes and the probability is \(\dfrac{20}{60}\) | B0 |
| Ticks Yes and because her total is higher | B0 |