ST1: Hypothesis Formulation
Learn how to formulate testable hypotheses for statistical enquiries, including the difference between null and alternative hypotheses and how to identify the variables involved.
Hypothesis Formulation
Hypothesis Formulation
Learn how to formulate testable hypotheses for statistical enquiries, including the difference between null and alternative hypotheses and how to identify the variables involved.
Key Fact: A hypothesis is a testable statement that predicts the outcome of an investigation.
Key Fact: A good hypothesis is specific, measurable and can be tested using data.
Key Fact: The null hypothesis (H₀) states there is no difference, no effect or no relationship — it is the default position.
Key Fact: The alternative hypothesis (H₁) states there is a difference, an effect or a relationship.
Key Fact: Statistical tests aim to find evidence to reject the null hypothesis in favour of the alternative.
Key Fact: An independent variable is the variable you change or categorise; a dependent variable is the one you measure.
Key Fact: A confounding variable is an extra variable you did not account for that may affect the result.
Key Fact: Hypotheses should use precise language: avoid vague terms like 'might' or 'could'.
Key Fact: A one-tailed hypothesis predicts the direction of the effect (e.g. 'taller than'); a two-tailed hypothesis predicts a difference but not the direction.
Key Fact: At GCSE level you typically write hypotheses as plain statements, not in formal H₀/H₁ notation, but you should understand the concept.
Key Fact: A hypothesis must be falsifiable — it must be possible for data to show it is wrong.
Key Fact: Hypotheses often compare two groups or look for a relationship between two variables.
📋 Key Vocabulary and Concepts
For Hypothesis Formulation, you must know:
- Hypothesis: A testable prediction about the outcome of an investigation.
- Null hypothesis (H₀): The hypothesis that there is no difference, effect or relationship.
- Alternative hypothesis (H₁): The hypothesis that there is a difference, effect or relationship.
- Independent variable: The variable that is changed or categorised by the investigator.
- Dependent variable: The variable that is measured or observed for changes.
- Confounding variable: A variable other than the independent variable that may affect the dependent variable.
❓ Practice Questions
Q: What is a hypothesis?
Q: What does the null hypothesis state?
Q: Write a suitable hypothesis for investigating whether Year 11 students spend more time on homework than Year 10 students.
Q: Why must a hypothesis be testable?
Q: What is the difference between an independent and a dependent variable?
✅ Answers
- A testable statement predicting the outcome of a statistical investigation.
- That there is no difference, no effect or no relationship between the variables being studied.
- Year 11 students spend more time on homework per week than Year 10 students.
- So that data can be collected and analysed to determine whether the prediction is supported or not.
- The independent variable is the one you change or categorise; the dependent variable is the one you measure or observe.
🎯 Exam Tips
- Always write your hypothesis before collecting any data — never change it to fit results.
- Use precise comparative language: 'greater than', 'less than', 'there is a relationship between'.
- Make sure your hypothesis mentions both variables clearly.
- In the exam, you may be asked to write or evaluate a hypothesis — check it is specific and testable.
- Know the difference between null and alternative hypotheses even if you do not use H₀/H₁ notation.
📝 Exam Technique
GCSE Statistics Exam Tips — Hypothesis Formulation:
1. For Hypothesis Formulation questions, show every step of your working clearly — method marks count even if the final answer is wrong
2. Check your answer makes sense in context (estimation, units, reasonableness)
3. Use correct mathematical notation and state formulae before substituting values
4. If a Hypothesis Formulation question asks you to 'prove' or 'show', write a logical chain of reasoning with a conclusion line
5. For problem-solving, identify the topic first, then recall the relevant method
1. For Hypothesis Formulation questions, show every step of your working clearly — method marks count even if the final answer is wrong
2. Check your answer makes sense in context (estimation, units, reasonableness)
3. Use correct mathematical notation and state formulae before substituting values
4. If a Hypothesis Formulation question asks you to 'prove' or 'show', write a logical chain of reasoning with a conclusion line
5. For problem-solving, identify the topic first, then recall the relevant method
⚠️ Common Errors
✗ Writing a hypothesis as a question ✓ Writing a hypothesis as a clear statement, e.g. 'Students who revise more score higher.'
✗ Using vague language like 'might affect' in a hypothesis ✓ Using definite comparative language, e.g. 'Students who sleep 8+ hours perform better than those who sleep less.'
✗ Confusing independent and dependent variables ✓ Identifying the independent variable as what you change/categorise and the dependent variable as what you measure.
✗ Writing a hypothesis that cannot be tested with data ✓ Ensuring the hypothesis refers to measurable variables that can be investigated quantitatively or qualitatively.
✍️ Model Answer
Full-Mark Response
A student wants to investigate whether people who exercise regularly have a lower resting heart rate. Write a suitable hypothesis and identify the variables.
Hypothesis: People who exercise regularly have a lower resting heart rate than those who do not exercise regularly. Independent variable: Whether the person exercises regularly (categorised as 'exercises regularly' or 'does not exercise regularly'). Dependent variable: Resting heart rate (measured in beats per minute). The hypothesis is testable because both variables can be measured: exercise habits can be categorised and resting heart rate can be recorded. Data from both groups can then be compared using an appropriate diagram and summary statistic.
📊 AO Deep Dive
Assessment Objective Analysis
AO1 (Knowledge & Understanding): Demonstrate knowledge and understanding of hypothesis formulation, including data collection, presentation and calculation techniques relevant to Edexcel 1ST0 & AQA 8382.
AO2 (Application): Apply knowledge and understanding of hypothesis formulation to interpret data, reason statistically and draw conclusions in context.
AO3 (Evaluation): Evaluate statistical methods and conclusions, assessing appropriateness, reliability, validity and bias through the statistical enquiry cycle.
📝 Exam Questions by Topic
- AQA Past Papers - Topic Questions -- AQA
- Edexcel Past Papers - Topic Questions -- Edexcel
- CCEA Past Papers - Topic Questions -- CCEA
🎬 Video Resources
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🧠 Flashcards (Spaced Repetition)
📝 Exam Questions by Topic
🎯 Target Tests (Auto-Graded)
📝 Exam Questions by Topic
📄 Past Papers for Statistics (AQA)
- AQA Past Papers & Mark Schemes
- Edexcel Past Papers & Mark Schemes
- OCR Past Papers & Mark Schemes
- Eduqas Past Papers & Mark Schemes
- CCEA Past Papers & Mark Schemes
For the most accurate and up-to-date past papers, always check the official exam board websites.