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 | 1 |
| 5<x≤105 < x \leq 105<x≤10 | 9 |
| 10<x≤1510 < x \leq 1510<x≤15 | 19 |
| 15<x≤2515 < x \leq 2515<x≤25 | 14 |
| 25<x≤4025 < x \leq 4025<x≤40 | 7 |
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−202\displaystyle x = \frac{t - 20}{2}x=2t−20
Calculate the median and the standard deviation of ttt.
121 exam-style questions on OCR (MEI) A Level Maths 2.2 Data Presentation and Interpretation, covering 2.2.1 Types of data and standard diagrams, 2.2.2 Area in a histogram is proportional to frequency, 2.2.3 Cumulative frequency diagram, 2.2.4 Describe frequency distributions, 2.2.5 Samples and theoretical distributions, 2.2.6 Interpret a scatter diagram, 2.2.7 Distinct sections and outliers in scatter diagrams, 2.2.8 Correlation and causation, 2.2.9 Select or critique data presentation techniques, 2.2.10 Measures of central tendency, 2.2.11 Simple measures of spread, 2.2.12 Variance and standard deviation, 2.2.13 Outliers, 2.2.14 Cleaning data, and 2.2 Data Presentation and Interpretation. Each one has a worked solution and a mark scheme showing where the marks go.