A company is investigating how long it takes employees, t t\,t minutes, to get to an event. They produce a table below of coded times, x x\,x minutes, for a random sample of 50 employees.
| Coded Time (minutes) | Frequency |
|---|---|
| 0<x≤50 < x \leq 50<x≤5 | 3 |
| 5<x≤105 < x \leq 105<x≤10 | 8 |
| 10<x≤1510 < x \leq 1510<x≤15 | 18 |
| 15<x≤2515 < x \leq 2515<x≤25 | 14 |
| 25<x≤4025 < x \leq 4025<x≤40 | 7 |
Estimate the standard deviation of the coded times.
96 exam-style questions on Edexcel A 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.