A theatre is investigating how long it takes visitors, t t\,t minutes, to travel to an evening performance. They produce a table below of coded travel times, x x\,x minutes, for a random sample of 50 visitors.
| Coded Time (minutes) | Frequency |
|---|---|
| 0<x≤40 < x \leq 40<x≤4 | 3 |
| 4<x≤84 < x \leq 84<x≤8 | 8 |
| 8<x≤148 < x \leq 148<x≤14 | 21 |
| 14<x≤2214 < x \leq 2214<x≤22 | 12 |
| 22<x≤3222 < x \leq 3222<x≤32 | 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−303\displaystyle x = \frac{t - 30}{3}x=3t−30
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.