Higher June 2017 Paper 2 Q12
12. The table shows rainfall for each day during a month.
| Rainfall, \(r\) (mm) | Number of days |
|---|---|
| \(0 \leqslant r \lt 4\) | 2 |
| \(4 \leqslant r \lt 8\) | 7 |
| \(8 \leqslant r \lt 12\) | 10 |
| \(12 \leqslant r \lt 16\) | 8 |
| \(16 \leqslant r \lt 20\) | 3 |
Calculate an estimate for the mean daily rainfall. [4]
| Scheme | Marks | Comments |
|---|---|---|
| Mid-points 2, 6, 10, 14, 18 | B1 | |
| 2×2+6×7+10×10+14×8+18×3 (=312) | M1 | FT ‘their midpoints’ provided these are at the bounds or within the groups (4 + 42 + 100 + 112 + 54 = 312) |
| ÷ 30 | m1 | |
| 10.4(mm) | A1 | |
| (4) |