A histogram is drawn to represent the CO emissions, x x\,x g/km, of a sample of cars. The heights of the four bars are given in the table below.
| Class | Height of bar (cm) |
|---|---|
| 0.0≤x<0.10.0 \le x < 0.10.0≤x<0.1 | 1.2 |
| 0.1≤x<0.20.1 \le x < 0.20.1≤x<0.2 | 3.6 |
| 0.2≤x<0.40.2 \le x < 0.40.2≤x<0.4 | 3.0 |
| 0.4≤x<0.80.4 \le x < 0.80.4≤x<0.8 | 0.9 |
There are 36 cars in the class 0.1≤x<0.20.1 \le x < 0.20.1≤x<0.2.
Show that the sample contains 144 cars.
Estimate the number of cars in the sample with a CO emission of at least 0.5 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.