Geographical Investigations » Presenting, Analysing and Evaluating Data
What you'll learn this session
Study time: 30 minutes
Cambridge spec: Enquiry skills for Paper 4
- Choose the best graph or map for fieldwork data, and say why
- Describe patterns in results and link them to geography
- Judge a hypothesis as true, partly true or false
- Evaluate the data and suggest improvements and extension work
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Unlock This CourseChoosing how to present the data
The last stages of an investigation are presenting, analysing, concluding and evaluating. Paper 4 gives you fieldwork results in tables or graphs and asks which technique suits them, what they show and how far they support the hypothesis. How to draw each graph is in the lessons on graphs. Here the skill is choosing, and giving a reason.
Ask two questions: what type of data is it, and what do I want to show?
| Technique | Best for | Fieldwork example |
|---|---|---|
| Line graph | Change over time | Pedestrians per hour through the day |
| Bar graph | Comparing separate categories | Visitors by type of transport |
| Divided bar graph | Parts of a whole at several sites | Shop types in three streets |
| Histogram | Grouped continuous data in equal classes | Pebble lengths in 10 mm classes |
| Pie graph | Shares of one whole, with few categories | Questionnaire answers: yes, no, unsure |
| Pictogram | Simple counts, easy to read | Cars counted outside a school |
| Scatter graph with best-fit line | A relationship between two variables | Channel width against distance downstream |
| Dispersion graph | How spread out values are | Where shops sit along a street |
| Triangular graph | Three parts that add to 100% | Sand, silt and clay in soil |
| Radial graph | Data around a circle, such as direction or time of day | Visitors by compass direction of origin |
| Rose chart | Direction data | Wind direction on a beach |
| Kite diagram | Change in abundance along a transect | Plant cover across sand dunes |
| Flow diagram | Movement between places, with line width for amount | Shoppers travelling to a centre |
| Choropleth map | Values shaded by area | Environmental quality score by street |
| Isoline map | Values changing across an area, joined by lines of equal value | Pedestrian counts across a town centre |
Key terms:
- Isoline: a line on a map joining places with the same value.
Giving a reason
Name the technique, then link it to the data: "A scatter graph with a best-fit line is suitable because both variables are numbers and the hypothesis is about a relationship." Say what is wrong with a poor choice too. A pie graph with ten tiny slices is hard to read.
Analysis and interpretation
Analysis means describing the pattern in the graph or table. Interpretation means saying why, using geographical knowledge. Take three steps.
📈 Trend
State the overall pattern: increases, decreases or no pattern.
🔢 Data
Quote figures with units, such as the highest, the lowest and the change.
❓ Anomaly
Point out any result that does not fit and suggest a reason.
Then explain. A reason you suggest for an anomaly is a possible cause, not a certainty.
Worked example: a river study
A class tested the hypothesis "Channel width and depth increase downstream" on the made-up River Kell. Table 1 shows their results.
| Site | Distance from source (km) | Width (m) | Depth (cm) |
|---|---|---|---|
| 1 | 1 | 2.0 | 12 |
| 2 | 3 | 3.1 | 18 |
| 3 | 5 | 4.4 | 25 |
| 4 | 7 | 4.6 | 21 |
| 5 | 9 | 7.2 | 38 |
| 6 | 11 | 8.1 | 41 |
Present
Both width and distance are numbers, and the hypothesis is about a relationship. A scatter graph with a best-fit line suits it.
Analyse
Width increases with distance, from 2.0 m at site 1 to 8.1 m at site 6, about four times wider. Depth also increases, from 12 cm to 41 cm, except at site 4, where it falls to 21 cm. This anomaly could be a shallow stretch of river, or a measurement taken in a different part of the channel. Both patterns fit the Bradshaw model, where rivers get wider and deeper downstream as more water joins and the channel erodes.
Making a conclusion
A conclusion is a judgement on the hypothesis, or on the aim of the investigation, supported by evidence from the results. Use one of three verdicts:
- True: the evidence supports all of it.
- Partly true: some of it is supported, but not all.
- False: the evidence does not support it.
Conclusion for the River Kell
Width increases at every site, so that part is true. Depth increases overall but falls at site 4, so that part is only partly true. The hypothesis is therefore partly true: width clearly supports it, and depth supports it with one exception.
Evaluation
Evaluation means judging how good the investigation was. Paper 4 asks about the reliability of the data and the weaknesses of the methods, then improvements and further work.
| Weakness | Why it matters | Improvement |
|---|---|---|
| Only six sites | Small sample, so one odd result has a big effect | Use more sites, spaced evenly |
| One reading at each site | A mistake would go unnoticed | Repeat three times and take the mean |
| One day only | Recent rain could change the width and depth | Repeat on another day |
| Measuring by hand | Human error in reading the ruler | Use the same equipment and the same people |
Finish with extension work: further study that builds on this one. Examples are testing other hypotheses, such as "Bedload gets smaller downstream", asking a new guiding question such as "How does bedload size change downstream?", or repeating the study on another river.
Key terms:
- Conclusion: a judgement on the hypothesis using the evidence.
- Evaluation: a judgement on how reliable the data and methods were, with improvements.
- Extension work: further investigation that builds on the original study.
Common mistakes
- Describing every number instead of the overall pattern.
- Saying "the hypothesis is proved". Say "supported" or "not supported" instead.
- Writing a conclusion with no figures from the results.
- Evaluating with "we should have done it better" and no named weakness.
Exam-style question
A class tested the hypothesis "Most visitors to Hartley Country Park live within 10 km of the park". They gave a questionnaire to 100 visitors at the entrance on one Saturday in August, asking only people who agreed to answer. Table 2 shows the distance visitors travelled. This is made-up data.
| Distance from home (km) | 0-5 | 5-10 | 10-15 | 15-20 |
|---|---|---|---|---|
| Number of visitors | 38 | 30 | 20 | 12 |
(a) Identify one graph that suits the data in Table 2. [1 mark]
(b) Describe the pattern shown in Table 2. [3 marks]
(c) Justify whether the results support the hypothesis. [3 marks]
(d) Evaluate the reliability of the results and suggest how the investigation could be improved. [6 marks]
Model answer
(a) A bar graph or a histogram. (1)
(b) The number of visitors decreases as distance increases. (1) The highest is 38 visitors from 0-5 km and the lowest is 12 from 15-20 km. (1) The decrease happens in every distance band. (1)
(c) The hypothesis is supported. (1) 38 + 30 = 68 visitors live within 10 km. (1) This is 68%, which is more than half, so it is most visitors. (1)
(d) Level 3 (5-6 marks): several weaknesses are named and explained, with linked improvements and a judgement on reliability. Level 2 (3-4 marks): some weaknesses or improvements, with limited explanation. Level 1 (1-2 marks): a simple or general point. A Level 3 response: only 100 people were asked on one Saturday, so the sample is small and may not represent weekdays or other seasons. Asking only willing people could be biased, because some groups, such as families in a hurry, may refuse. Distances were grouped in 5 km bands, so exact distances are lost. The results are fairly reliable for that day, but another day could give different totals. To improve: ask a larger sample, such as every 10th visitor, on weekdays and weekends. Repeating in different months would show whether the pattern changes.
Exam tip
In (c), support your verdict with figures from the table, such as the total you worked out.