FieldworkDeep Dive

Statistical Analysis

Part of Fieldwork Process and EnquiryGCSE Geography

This deep dive covers Statistical Analysis within Fieldwork Process and Enquiry for GCSE Geography. Revise Fieldwork Process and Enquiry in Fieldwork for GCSE Geography with 15 exam-style questions and 20 flashcards. This topic shows up very often in GCSE exams, so students should be able to explain it clearly, not just recognise the term. It is section 8 of 16 in this topic. Use this deep dive to connect the idea to the wider topic before moving on to questions and flashcards.

Topic position

Section 8 of 16

Practice

15 questions

Recall

20 flashcards

📐 Statistical Analysis

Statistical tools allow you to move beyond description ("the data shows a general increase") to rigorous analysis ("the data shows a strong positive correlation, confirmed by a Spearman's rank coefficient of +0.85, which is statistically significant at the 95% confidence level"). These tools are part of the OCR B and AQA specifications and are directly examinable.

Measures of Central Tendency

These summarise the typical value in a dataset:

  • Mean: Add all values and divide by the number of values. Best used when data is normally distributed with no extreme outliers. A single very large or very small value will skew the mean significantly.
  • Median: The middle value when data is arranged in order. More robust than the mean when outliers are present — a single extreme reading cannot shift it significantly.
  • Mode: The most frequently occurring value. Most useful for categorical data (e.g., the most common land use type on a transect).
  • Measures of Spread

    These describe how variable the data is:

  • Range: Maximum value minus minimum value. Simple but sensitive to outliers — one extreme value inflates the range.
  • Interquartile range (IQR): The range of the middle 50% of values (Q3 minus Q1). Far more meaningful than the range when outliers are present, because it focuses on the bulk of the data.
  • Spearman's Rank Correlation Coefficient (rs)

    Spearman's rank tests whether there is a statistically significant relationship between two sets of ranked data. It is the statistical technique most commonly tested in GCSE geography fieldwork questions.

    How it works:

    Step 1: Rank both datasets. Assign rank 1 to the highest value, rank 2 to the second highest, and so on. Where two values are equal (tied), give them the average of the ranks they share.
    Step 2: Calculate d for each pair. For each data pair, subtract one rank from the other to find d (the difference in ranks).
    Step 3: Square d for each pair. Calculate d² for every pair, then sum all d² values to get Σd².
    Step 4: Apply the formula. rs = 1 − (6Σd² / n(n²−1)), where n is the number of data pairs.
    Step 5: Interpret the result. rs ranges from −1 to +1. A result of +1 = perfect positive correlation; −1 = perfect negative correlation; 0 = no correlation. Compare your rs value to the critical values table for your sample size and confidence level (usually 95%).

    Interpreting rs

    rs valueInterpretation
    +0.81 to +1.0Strong positive correlation — as Variable A increases, Variable B consistently increases
    +0.41 to +0.80Moderate positive correlation
    +0.01 to +0.40Weak positive correlation
    0No correlation
    −0.01 to −0.40Weak negative correlation
    −0.41 to −0.80Moderate negative correlation — as Variable A increases, Variable B decreases
    −0.81 to −1.0Strong negative correlation

    Percentage Change

    To compare change over time or between sites: Percentage change = ((New value − Old value) / Old value) × 100

    A positive result means an increase; a negative result means a decrease. This allows fair comparison between sites with different starting values.

    Identifying and Explaining Anomalies

    An anomaly is a data value that does not fit the overall trend — either higher or lower than expected. Anomalies are not mistakes to be hidden; they are evidence to be explained. In the exam, identifying an anomaly and offering a geographical explanation for it often earns two or three additional marks. Common explanations include local site conditions, measurement errors on the day, or genuine exceptions to the geographical model being tested.

    Quick Check: A student calculates a Spearman's rank value of +0.76 for their river velocity investigation. What does this tell them?

    Keep building this topic

    Read this section alongside the surrounding pages in Fieldwork Process and Enquiry. That gives you the full topic sequence instead of a single isolated revision point.

    Practice Questions for Fieldwork Process and Enquiry

    Which sampling method involves collecting data at regular, pre-set intervals — for example, every 10 metres along a transect?

    • A. Random sampling
    • B. Opportunistic sampling
    • C. Systematic sampling
    • D. Stratified sampling
    1 markfoundation

    Define random sampling and state one advantage of using it in fieldwork.

    2 marksstandard

    Quick Recall Flashcards

    What is secondary data?
    Data collected by someone else and used later.
    What is primary data?
    Data collected first-hand by the student or researcher.

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