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.
8 exam-style questions on WJEC A Level Maths 2.2.6 Data presentation and interpretation. Each one has a worked solution and a mark scheme showing where the marks go.