The CO emissions, x x\,x g/km, of 120 petrol cars are summarised in the table below.
| 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 | 36 |
| 0.2≤x<0.30.2 \le x < 0.30.2≤x<0.3 | 42 |
| 0.3≤x<0.50.3 \le x < 0.50.3≤x<0.5 | 24 |
| 0.5≤x<0.90.5 \le x < 0.90.5≤x<0.9 | 6 |
For a sample of diesel cars, the CO emissions have mean 0.15 g/km and standard deviation 0.05 g/km.
Estimate the mean CO emission of the 120 petrol cars.
Estimate the standard deviation of the CO emissions of the 120 petrol cars.
Compare the CO emissions of the petrol cars and the diesel cars.
39 exam-style questions on AQA A Level Maths 2.2.3 Central tendency, variation and standard deviation. Each one has a worked solution and a mark scheme showing where the marks go.