To process a small dataset, sort it, check it, then calculate only the summaries that help answer the investigation aim. Typical choices are the total, the mean, the median, the range and a percentage. This appears when you analyse your own results or an invented dataset in a written paper.
It is the first skill in fieldwork analysis and evaluation, and it builds on the planning ideas in fieldwork design and sampling.
What does “processing” actually involve?
Raw results are what you wrote in the field. Processed results are the numbers that let you see a pattern. Processing means putting values in order, working out summaries and presenting them in a clear table.
Work in this order, and show each step.
- Check the data. Look for missing values, units and obvious typing errors.
- Sort the values from smallest to largest.
- Choose the summaries that answer the aim.
- Calculate and record the working, including the units.
- Round sensibly at the end only.
Worked example
The data below is invented. A class counts pedestrians passing seven points along a street in ten minutes. Each point is a different distance from the town centre.
| Site | Distance from centre (km) | Pedestrians in 10 min |
|---|---|---|
| A | 0.1 | 84 |
| B | 0.3 | 71 |
| C | 0.5 | 66 |
| D | 0.8 | 52 |
| E | 1.2 | 47 |
| F | 1.6 | 39 |
| G | 2.0 | 35 |
Total: 84 + 71 + 66 + 52 + 47 + 39 + 35 = 394 pedestrians.
Mean: 394 ÷ 7 = 56.28…, so 56.3 pedestrians per site.
Median: the values are already sorted. There are seven, so the middle one is the 4th value: 52.
Range: 84 − 35 = 49.
Percentage at the busiest site: 84 ÷ 394 × 100 = 21.3%, so about a fifth of all pedestrians counted were at site A.
The mean (56.3) and median (52) are close, which tells you no single value is dragging the average away. Both are reasonable here.
What mistake costs marks?
A common slip is to take the middle value of an unsorted list as the median.
Mistaken working: the counts are written as 52, 84, 35, 66, 47, 71, 39. The student picks the 4th value, 66, as the median.
The list was not in order, so the 4th value means nothing. Sorted, the values are 35, 39, 47, 52, 66, 71, 84, and the median is 52. Always sort first, then count in from both ends.
Check yourself
All data is invented.
1. Five litter counts are 12, 15, 9, 20 and 14. Find the mean, median and range.
Show answer
Total: 12 + 15 + 9 + 20 + 14 = 70. Mean: 70 ÷ 5 = 14.
Sorted: 9, 12, 14, 15, 20, so the median is 14. Range: 20 − 9 = 11.
2. A student interviews 60 people and 18 say they walk to the shops. What percentage is that?
Show answer
18 ÷ 60 × 100 = 30%.
3. Four sand-depth readings are 6, 8, 11 and 15 cm. Find the median and the mean.
Show answer
There are four values, so the median is the mean of the middle two: (8 + 11) ÷ 2 = 9.5 cm. The mean is (6 + 8 + 11 + 15) ÷ 4 = 40 ÷ 4 = 10 cm.
Where this leads next
With the numbers processed, the next step is choosing how to show them: select a graph that answers the question. The statistics and distribution explorer lets you check your own mean and median on practice data, and the fieldwork analysis practice set mixes all the skills.
Some students calculate everything correctly but lose marks because the figures are never tied to the aim. A teacher on our online one-to-one Geography tuition can look at your working with you and find exactly where the link breaks.