A college is investigating how long it takes students, t t\,t minutes, to cycle to campus. They produce a table below of coded journey times, x x\,x minutes, for a random sample of 50 students.
| Coded Time (minutes) | Frequency |
|---|---|
| 0<x≤50 < x \leq 50<x≤5 | 5 |
| 5<x≤95 < x \leq 95<x≤9 | 8 |
| 9<x≤159 < x \leq 159<x≤15 | 20 |
| 15<x≤2415 < x \leq 2415<x≤24 | 11 |
| 24<x≤3624 < x \leq 3624<x≤36 | 6 |
Use linear interpolation to estimate the median of the coded times.
Estimate the standard deviation of the coded times.
The coded data was calculated using the formula: x=t−152\displaystyle x = \frac{t - 15}{2}x=2t−15
Calculate the median and the standard deviation of ttt.
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.