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Data handling is a core geographical skill tested in every Edexcel B exam paper. You need to be able to draw graphs accurately, interpret what they show, calculate statistical measures, describe trends, and identify anomalies. These skills are worth a significant number of marks across all three papers, and they are skills you can improve dramatically with practice.
This lesson provides a comprehensive revision of the data skills you need, with worked examples and practice techniques for each one.
Bar charts are the most commonly required graph in the exam. Follow these rules:
| Rule | Why |
|---|---|
| Equal bar widths | Ensures visual fairness between categories |
| Equal gaps between bars | Distinguishes bars and improves readability |
| Y-axis starts at zero | Avoids exaggerating differences |
| Equal intervals on y-axis | Ensures accurate representation |
| Clear labels on both axes with units | Allows the reader to understand the data |
| A descriptive title | Tells the reader what the graph shows |
Common exam instruction: "Using the data in Table 2, complete the bar chart on Figure 5." (3 marks)
How to score full marks:
| Rule | Why |
|---|---|
| Plot points accurately | Incorrect plotting = incorrect answer |
| Connect points with straight lines (ruler) | Shows change clearly |
| Label axes with units | Enables interpretation |
| Use different line styles for multiple datasets | Distinguishes between lines |
| Rule | Why |
|---|---|
| Plot each point using both x and y values | Shows the relationship between variables |
| Do NOT connect the points | Scatter graphs show correlation, not sequence |
| Draw a line of best fit if asked | Shows the general trend |
| Equal points above and below the line of best fit | Ensures the line represents the data fairly |
Exam Tip: When completing a graph in the exam, use a sharp pencil and a ruler. Accuracy matters — if your bar is plotted at 45 when the correct value is 48, you will lose the mark. Take your time and double-check each plotted point against the data table.
Use this vocabulary to describe trends:
| Trend | Language to Use |
|---|---|
| Increase | "Values rise from X to Y," "there is a steady/rapid increase" |
| Decrease | "Values fall from X to Y," "there is a gradual/sharp decline" |
| Fluctuation | "Values fluctuate between X and Y," "there is no clear trend" |
| Plateau | "Values level off at approximately X," "there is little change between..." |
| Peak | "Values reach a maximum of X in [month/location]" |
| Trough | "Values reach a minimum of X in [month/location]" |
| Anomaly | "Site C is an anomaly, showing a higher/lower value than the trend suggests" |
| Correlation | Description | Visual Pattern |
|---|---|---|
| Strong positive | As X increases, Y increases consistently | Points close to line rising left to right |
| Weak positive | General tendency for Y to increase with X, but scattered | Points loosely rising left to right |
| Strong negative | As X increases, Y decreases consistently | Points close to line falling left to right |
| Weak negative | General tendency for Y to decrease with X, but scattered | Points loosely falling left to right |
| No correlation | No clear relationship | Points scattered randomly |
Mean = Sum of all values / Number of values
Example: Pedestrian counts at 5 sites: 45, 62, 38, 71, 54
Mean = (45 + 62 + 38 + 71 + 54) / 5 = 270 / 5 = 54 people
The most frequent value. If data is: 3, 4, 4, 5, 6, 7, 4, 8 → Mode = 4
Range = Highest - Lowest
Range = 71 - 38 = 33 people
Data (ordered): 12, 15, 18, 22, 25, 28, 31, 35, 38, 42, 45, 50
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