For a sample of 25 cars, the CO emission x x\,x g/km of each car is recorded. It is given that
∑x=6.25\sum x = 6.25∑x=6.25 and ∑x2=1.6525\sum x^2 = 1.6525∑x2=1.6525
For this question, a value is defined to be an outlier if it is more than two standard deviations from the mean.
Show that the mean is 0.25 g/km and the standard deviation is 0.06 g/km.
Find, using set notation, the set of CO emissions that would be classed as outliers for this sample.
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.