What kinds of data are there, and how do you collect them well using questionnaires, surveys and data-collection sheets?
Classify data as qualitative or quantitative, discrete or continuous, primary or secondary, and design good questionnaires, data-collection sheets and surveys that avoid bias and leading questions.
A CCEA GCSE Statistics answer on collecting data: types of data, primary and secondary sources, designing questionnaires and data-collection sheets, leading and biased questions, response classes, and pilot surveys.
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What this dot point is asking
Good data collection is the second stage of the enquiry cycle, and CCEA tests it heavily. You must classify data correctly (qualitative or quantitative, discrete or continuous, primary or secondary), and you must be able to criticise and improve questionnaires and data-collection sheets. The questionnaire question is one of the most common in the paper, and it always rewards spotting leading or biased wording and writing clear, non-overlapping response options.
Types of data
Classifying data correctly decides which charts and averages are valid, so it is a frequent first part of a question.
A useful test: if you count it, it is discrete; if you measure it, it is continuous. Money is usually treated as discrete (it goes up in pence), while time, length and mass are continuous.
Primary and secondary data
Data is also classified by its source.
Designing a questionnaire
A questionnaire turns your data needs into questions. CCEA repeatedly asks you to criticise and improve one.
A good question is clear, relevant, unbiased and not leading, and a closed question needs response options that are exhaustive and non-overlapping. Common faults to spot and fix:
- Leading questions that push an answer ("Don't you agree that...?").
- Biased or emotive wording ("our excellent canteen").
- Overlapping response boxes (such as 0 to 10 and 10 to 20 - which box holds 10?).
- No time frame ("How often do you exercise?" needs "per week").
- Sensitive or embarrassing questions that reduce honest answers.
Data-collection sheets and pilots
A data-collection sheet (or tally chart) organises data as it is gathered, with clear, non-overlapping classes ready for analysis. Before a questionnaire or survey is used in full, it should be tested with a pilot survey: a small trial run that reveals confusing questions, missing options or practical problems, so they can be fixed before the real data collection. A pilot saves a whole enquiry from being wasted on flawed questions.
Why this matters
Correct data classification controls every later choice of chart and average, so it underpins the whole of the processing stage. The questionnaire-criticism question is one of the highest-frequency items on CCEA papers and is pure technique once you know the faults to look for. Designing fair surveys is also a genuine life skill: opinion polls, market research and government surveys all stand or fall on the quality of their questions and collection sheets.
Exam-style practice questions
Practice questions written in the style of CCEA exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
CCEA-style4 marksA questionnaire asks: 'Don't you agree that our excellent school canteen offers great value?' Give two criticisms of this question and write an improved version with response options.Show worked answer →
Two criticisms (one mark each): it is a leading question (the words "excellent" and "great value" push the respondent towards agreeing); and it is biased or double-barrelled, mixing quality and value and offering no balanced choice. It also has no time frame and no response options.
An improved version (two marks, one for a neutral question, one for suitable non-overlapping options): "How would you rate the value for money of the school canteen?" with tick-box options such as Very poor / Poor / Average / Good / Very good. The options must be clear, cover all answers and not overlap.
CCEA-style3 marksClassify each of these as discrete or continuous data: (a) the number of cars in a car park, (b) the time taken to run 100 m, (c) shoe size.Show worked answer →
(a) Number of cars: discrete - it can only take whole-number values (you cannot have half a car). One mark.
(b) Time to run 100 m: continuous - it can take any value in a range and is only limited by the accuracy of measurement. One mark.
(c) Shoe size: discrete - it takes separate listed values (such as 7, 7.5, 8) rather than any value in a range. One mark. Discrete data is counted; continuous data is measured.
Related dot points
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A CCEA GCSE Statistics answer on the statistical enquiry cycle: writing a hypothesis, planning an investigation, populations and samples, the four stages of the cycle, and evaluating and refining an enquiry.
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A CCEA GCSE Statistics answer on tabulating and displaying data: frequency and two-way tables, pictograms, bar charts including composite and comparative bar charts, pie charts and stem-and-leaf diagrams, and choosing the right display.
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Sources & how we know this
- CCEA GCSE Statistics (2017) specification (2260) — CCEA (2017)