The CO emission x x\,x g/km of each of 150 petrol cars is recorded. For these cars,
∑x=33\sum x = 33∑x=33 and ∑x2=7.8\sum x^2 = 7.8∑x2=7.8
For a sample of diesel cars, the CO emissions have mean 0.15 g/km and standard deviation 0.04 g/km.
Calculate the mean CO emission of the 150 petrol cars.
Calculate the standard deviation of the CO emissions of the 150 petrol cars.
Compare the CO emissions of the petrol cars and the diesel cars.
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.