Categorical, Ordinal and Ranked Data
Practise Categorical, Ordinal and Ranked Data for GCSE Statistics with this free worksheet and full mark scheme — Foundation and Higher exam-style questions with worked answers for AQA and Edexcel. Data can be categorical (nominal), ordinal (ordered categories), or measured on interval and ratio scales.
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These worksheets and mark schemes are original, written for Virtus Academy and checked against the current AQA and Edexcel specifications. Every worksheet comes with a full mark scheme.
Topic overview
Qualitative data divides further into categorical, ordinal and ranked data, and the distinction affects which averages can be used.
Categorical data has no natural order — eye colour, favourite subject, brand of phone. Only the mode is meaningful.
Ordinal data has a natural order but the gaps between categories are not necessarily equal. Exam grades, satisfaction ratings and finishing positions are ordinal. Because there is an order, the median can be found as well as the mode, but the mean cannot be calculated meaningfully. Ranked data assigns positions in order, and is a form of ordinal data used in rank correlation.
Revision notes
Categorical data
Data with no natural order, such as eye colour, favourite subject or type of transport.
The categories can be listed in any order without losing meaning. Only the mode is available as an average.
Ordinal data
Data with a natural order but not necessarily equal gaps between categories.
Examples: exam grades A to E, satisfaction ratings from poor to excellent, finishing positions in a race. The median can be found because the data can be put in order.
Ranked data
Data where items are assigned positions in order, such as 1st, 2nd, 3rd.
It is a form of ordinal data. Ranking is used in Spearman's rank correlation coefficient, where the actual values are replaced by their positions in order.
Key points
- Categorical data has no natural order.
- Only the mode is available for categorical data.
- Ordinal data has a natural order.
- Ordinal gaps are not necessarily equal.
- The median can be found for ordinal data.
- Ranked data assigns positions in order.
Worked examples
Example 1
State whether exam grades are categorical or ordinal data. [1 mark]
Working
Example 2
Explain why the median can be found for ordinal data but the mean cannot. [2 marks]
Working
Example 3
A survey records satisfaction as poor, fair, good or excellent. State the type of data. [1 mark]
Working
Common mistakes
Treating ordinal data as fully numerical.
The gaps between categories are not necessarily equal, so the mean is not meaningful.
Saying categorical data can be ordered.
By definition it has no natural order.
Confusing ranked with quantitative.
A rank is a position, not a measurement.
Finding a median of categorical data.
Without an order there is no meaningful middle value.
Exam tips
- Ask whether the categories have a natural order.
- Remember only the mode works for categorical data.
- Explain the ordinal mean problem through unequal gaps.
- Link ranked data to Spearman's rank correlation.
Key terms
- Categorical
- Qualitative data with no natural order.
- Ordinal
- Qualitative data with a natural order.
- Ranked
- Data assigned positions in order.
- Median
- The middle value, available for ordinal data.
Related topics
Written and reviewed against the current AQA and Edexcel specifications. Spotted an error? Let us know.