Foundation November 2022 Paper 3 Q28
28 Here are the results after 250 spins of a coin.
| Heads | 128 |
|---|---|
| Tails | 122 |
The coin is spun an extra 50 times.
After all 300 spins, the relative frequency of Heads is 0.49
For the extra 50 spins, work out number of Heads : number of Tails [3 marks]
| Answer | Mark | Comments |
|---|---|---|
| Alternative method 1 | ||
| \(0.49 \times (250 + 50)\) or \(0.49 \times 300\) or 147 | M1 | oe |
| their \(147 - 128\) or 19 | M1dep | |
| 19 : 31 | A1 | SC2 answer 31 : 19 |
| Alternative method 2 | ||
| \((1 - 0.49) \times (250 + 50)\) or \(0.51 \times 300\) or 153 | M1 | oe |
| their \(153 - 122\) or 31 | M1dep | |
| 19 : 31 | A1 | SC2 answer 31 : 19 |
Additional guidance
| Up to M2 may be awarded for correct work, with no or incorrect answer, even if this is seen amongst multiple attempts | |
| 147 : 153 or 153 : 147 | M1M0A0 |
| 0.49 : 0.51 | M0M0A0 |
| Beware of 147 and 153 from incorrect working \(122 + 25 = 147\) \(128 + 25 = 153\) | M0 M0 |