The CO emissions of a sample of 50 cars have mean 0.28 g/km and standard deviation 0.08 g/km.
Two of the recorded values, 0.62 g/km and 0.58 g/km, are found to be errors and are removed from the sample. All other values are correct.
Find the mean of the remaining 48 values.
Find the standard deviation of the remaining 48 values.
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.