The CO2 _2\,2 emissions, x x\,x g/km, of 200 cars are summarised in the table below.
| CO2 _2\,2 emission (g/km) | Frequency |
|---|---|
| 120≤x<160120 \le x < 160120≤x<160 | 30 |
| 160≤x<200160 \le x < 200160≤x<200 | 64 |
| 200≤x<240200 \le x < 240200≤x<240 | 70 |
| 240≤x<280240 \le x < 280240≤x<280 | 26 |
| 280≤x<320280 \le x < 320280≤x<320 | 10 |
For this question, a value is defined to be an outlier if it is greater than Q3+1.5(Q3−Q1)Q_3 + 1.5(Q_3 - Q_1)Q3+1.5(Q3−Q1).
Use linear interpolation to estimate Q1 Q_1\,Q1 and Q3Q_3Q3.
Hence estimate the interquartile range, and determine whether a car with a CO2 _2\,2 emission of 320 g/km would be classed as an outlier.
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.