The CO emissions of a sample of 40 cars have mean 0.30 g/km and standard deviation 0.09 g/km.
It is then found that one car's CO emission was entered as 0.85 g/km when the correct value is 0.45 g/km. All other values are correct.
Calculate the mean of the 40 corrected values.
State, with a reason, the effect of the correction on the standard deviation.
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.