Edexcel GCSE Statistics

A statistical investigation is not a single calculation. It is a sequence of decisions, and the **statistical enquiry cycle** names the stages in the order they happen. The same stages organise the whole of GCSE Statistics: a question in any topic is usually asking about one stage, or about how two neighbouring stages depend on each other. ## The five stages 1. Plan the enquiry. 2. Collect the data. 3. Process and represent the data. 4. Interpret the results. 5. Communicate the findings and evaluate the work. The word cycle matters. The evaluation at the end usually shows something that could be done better, or a new question the results have raised, so the investigation goes round again with a refined hypothesis, a better sample or a different diagram. Conclusions in statistics are built up through repeated testing and refinement and are rarely settled by a single pass. ## Planning Planning starts with a **question** or a **hypothesis**, a statement that can be tested by collecting and analysing data. "As motorcycles get older, their value goes down" is a hypothesis. "Are motorcycles worth less when they are old?" is only a question, and it does not say what result would support or contradict it. The plan then settles three things, each with a reason: - which data is needed, and the way it will be gathered and written down; - how to process the data once it is collected; - how to represent the data so that it answers the question. A good plan also looks ahead to the things…