An extract from the Large Data Set gives the CO emissions, in g/km, of 105 petrol cars. The extract is summarised in the table below, where x x\,x is the CO emission in g/km.
| CO emission (g/km) | Frequency |
|---|---|
| 0.0≤x<0.10.0 \le x < 0.10.0≤x<0.1 | 12 |
| 0.1≤x<0.20.1 \le x < 0.20.1≤x<0.2 | 30 |
| 0.2≤x<0.40.2 \le x < 0.40.2≤x<0.4 | 40 |
| 0.4≤x<0.50.4 \le x < 0.50.4≤x<0.5 | 14 |
| 0.5≤x<0.80.5 \le x < 0.80.5≤x<0.8 | 9 |
A histogram is drawn to represent these data.
On the histogram, the bar for 0.1≤x<0.2 0.1 \le x < 0.2\,0.1≤x<0.2 is taller than the bar for 0.2≤x<0.40.2 \le x < 0.40.2≤x<0.4, even though fewer cars lie in the class 0.1≤x<0.20.1 \le x < 0.20.1≤x<0.2. Explain why.
Estimate the number of these 105 cars with a CO emission of less than 0.15 g/km.
244 exam-style questions on AQA A Level Maths 2.2 L: Data presentation and interpretation, covering 2.2.1 Single-variable data diagrams, 2.2.2 Scatter diagrams and correlation, 2.2.3 Central tendency, variation and standard deviation, 2.2.4 Outliers and cleaning data, and 2.2 L: Data presentation and interpretation. Each one has a worked solution and a mark scheme showing where the marks go.