Higher June 2019 Paper 3 Q17
17 A factory makes kettles.
Four samples of kettles are tested for faults.
Each sample has size 200
Here are the relative frequencies of faulty kettles in the samples.
| Sample | P | Q | R | S |
|---|---|---|---|---|
| Relative frequency | 0.03 | 0.035 | 0.015 | 0.01 |
Work out the range of the number of faulty kettles in the four samples. [3 marks]
| Answer | Mark | Comments |
|---|---|---|
| Alternative method 1 | ||
| \(0.03 \times 200\) or 6 or \(0.035 \times 200\) or 7 or \(0.015 \times 200\) or 3 or \(0.01 \times 200\) or 2 | M1 | |
| \(0.035 \times 200\) or 7 and \(0.01 \times 200\) or 2 | M1dep | |
| 5 | A1 | |
| Alternative method 2 | ||
| 0.035 – 0.01 or 0.025 | M1 | |
| their \(0.025 \times 200\) | M1dep | |
| 5 | A1 | |
Additional guidance
| Condone errors in calculating 6 or 3 as only the values 7 and 2 are required to correctly answer the question eg 5, 7, 3, 2 the range is 7 – 2 = 5 | M1M1A1 |
| 5 on answer line does not imply full marks, method must be checked eg \(0.03 \times 200 = 8 \quad 8 - 3 = 5\) | M1M0A0 |