4MA0 Higher June 2017 Paper 3 Q11
11 The table gives information about the ages of all the 90 adults in a supermarket.
| Age (\(t\) years) | Frequency |
|---|---|
| \(20 \lt t \leqslant 30\) | 4 |
| \(30 \lt t \leqslant 40\) | 28 |
| \(40 \lt t \leqslant 50\) | 30 |
| \(50 \lt t \leqslant 60\) | 16 |
| \(60 \lt t \leqslant 70\) | 8 |
| \(70 \lt t \leqslant 80\) | 4 |
One of these 90 adults is picked at random.
| Age (\(t\) years) | Cumulative frequency |
|---|---|
| \(20 \lt t \leqslant 30\) | |
| \(20 \lt t \leqslant 40\) | |
| \(20 \lt t \leqslant 50\) | |
| \(20 \lt t \leqslant 60\) | |
| \(20 \lt t \leqslant 70\) | |
| \(20 \lt t \leqslant 80\) |

All of these adults with an age greater than 65 years receive a discount on their shopping bill.
| Scheme | Marks |
|---|---|
| \(\dfrac{16 + 8 + 4}{90}\) | M1 |
| \(\dfrac{28}{90}\) oe | A1 |
| (2) |
Notes
A1: for \(\dfrac{28}{90}\) oe E.g. \(\dfrac{14}{45}\), 0.31(1…), 31(.1…)%
| Scheme | Marks |
|---|---|
| 4, 32, 62, 78, 86, 90 | B1 |
| (1) |
Notes
B1: cao
| Scheme | Marks |
|---|---|
| (30, 4) (40, 32) (50, 62) (60, 78) (70, 86) (80, 90) | M1 |
| correct cf graph | A1 |
| (2) |
Notes
M1: (ft from sensible table i.e. clear attempt at addition)
for at least 4 points plotted correctly at end of interval
or
for all 6 points plotted consistently within each interval in the freq table at the correct height (e.g. used values of 25, 35, 45 etc on age axis)
A1: accept curve or line segments
accept curve that is not joined to (20,0)
| Scheme | Marks |
|---|---|
| E.g. reading from graph at \(t = 65\) or reading of 82 – 84 or mark on cf axis from using \(t = 65\) | M1 |
| 6 – 8 | A1 |
| (2) | |
| (7 marks) |
Notes
M1: for evidence of using graph at \(t = 65\)
ft from a cumulative frequency graph provided method is shown
A1: dep on a cf graph in part (c)
ft from a cumulative frequency graph provided method is shown