The time taken by 100 runners to complete a course is summarised below.
| Time (nearest minute) | Frequency |
|---|---|
| 0 - 9 | 3 |
| 10 - 19 | 14 |
| 20 - 29 | 34 |
| 30 - 39 | 29 |
| 40 - 49 | 15 |
| 50 - 59 | 5 |
Using the class midpoints, you may use: ∑fx=2990\sum fx = 2990∑fx=2990 and ∑fx2=102485\sum fx^2 = 102485∑fx2=102485
Use linear interpolation to estimate the median time.
Estimate the mean time.
Estimate the standard deviation.
32 exam-style questions on Edexcel AS Level Maths Measures of Location and Spread, covering 2.1 Measures of Central Tendency, 2.2 Other Measures of Location, 2.3 Measures of Spread, 2.4 Variance and Standard Deviation, and 2.5 Coding. Each one has a worked solution and a mark scheme showing where the marks go.