The distances travelled by 100 people to an event, recorded to the nearest mile, are summarised in the table below.
| Distance (nearest mile) | Frequency |
|---|---|
| 0–9 | 4 |
| 10–19 | 19 |
| 20–29 | 41 |
| 30–39 | 26 |
| 40–49 | 9 |
| 50–59 | 1 |
You may use ∑fx=2650\sum fx = 2650∑fx=2650 and ∑fx2=80 425\sum fx^2 = 80\,425∑fx2=80425, where the values of x x\,x are the class midpoints.
Use linear interpolation to estimate the median distance.
Estimate the mean distance.
Estimate the standard deviation of the distances.
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.