How is data collected, presented and analysed to inform design decisions?
Handling data in design, including collecting primary and secondary data, calculating measures of average (mean, median, mode) and range, presenting data with tables, bar charts, pie charts and line graphs, interpreting graphs and trends, and using statistics and probability to inform decisions about user needs, testing and quality.
A focused answer to the Edexcel 9DT0 content on handling data, covering primary and secondary data, mean, median, mode and range, presenting data with charts and graphs, interpreting trends, and using statistics and probability to inform design and quality decisions.
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What this dot point is asking
Edexcel wants you to handle data in design: collect primary and secondary data, calculate averages (mean, median, mode) and range, present data with tables and charts, interpret graphs and trends, and use statistics and probability to inform decisions about user needs, testing and quality.
The answer
Primary and secondary data
Averages and range
Presenting data
Choose the chart to suit the data:
- Table: organises raw values clearly.
- Bar chart: compares separate categories (preferred features, materials).
- Pie chart: shows proportions of a whole (colour choice as percentages).
- Line graph: shows a trend or relationship over a continuous variable (force against extension, sales over time).
- Histogram: shows the distribution of a measurement (the spread of user heights).
Interpreting graphs and trends
Reading data means spotting patterns and trends: a rising line shows an increasing relationship, a clustered histogram shows where most users fall, and the most popular bar shows the favoured option. Interpretation, not just plotting, is what informs the design.
Statistics and probability in decisions
Statistics turn data into decisions: the mean and spread of body measurements set product dimensions (with the right percentile), the mode of user preferences guides features, and test data (averaged and graphed) shows whether a design meets the specification. Probability measures likelihood, used for failure rates, reliability and risk assessment in quality.
Examples in context
A designer of a school bag surveys real students (primary data) for back length and feature preferences and consults anthropometric tables (secondary data), then tabulates the results and shows preferred features as a bar chart and colour choice as a pie chart. The mean and percentile spread of body measurements set the bag's dimensions, and the most-requested features (the mode) shape the specification. In testing, sample failure loads are averaged and their range checked to judge quality and consistency. Collecting the right data, presenting it in the right chart, and using averages, spread and trends to justify decisions, are exactly the maths-in-context skills Edexcel rewards.
Try this
Q1. Find the mean and range of: . [2 marks]
- Cue. Mean ; range .
Q2. State the difference between primary and secondary data. [2 marks]
- Cue. Primary data is collected first-hand by the designer for this project (surveys, measurements); secondary data comes from existing sources (tables, standards, reports).
Q3. Which chart best shows the proportion of users choosing each of four colours, and why? [2 marks]
- Cue. A pie chart, because it shows each colour as a slice of the whole, making the proportions easy to compare.
Exam-style practice questions
Practice questions written in the style of Pearson Edexcel exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
Edexcel 20194 marksA designer surveys the heights (in cm) of seven users: 162, 170, 158, 175, 170, 168, 181. Calculate the mean, median, mode and range.Show worked answer →
Award one mark for each correct statistic.
Mean: cm (to 1 d.p.).
Median: order the values (158, 162, 168, 170, 170, 175, 181); the middle (4th of 7) is cm.
Mode: the most frequent value is cm (it appears twice).
Range: largest minus smallest cm.
Markers reward the correct mean ( cm), median ( cm), mode ( cm) and range ( cm), with method shown for the mean and median.
Edexcel 20216 marksExplain how a designer would collect and use data to decide the dimensions and features of a new school bag, referring to types of data and how it is presented and analysed.Show worked answer →
Extended-response item marked on levels (types of data, presentation and how the analysis informs the design).
Primary data: the designer surveys or measures real target users (students), gathering anthropometric data (back length, shoulder width) and preferences (capacity, pockets, colour). Secondary data: published standards, anthropometric tables and competitor research add context cheaply.
Presentation: numerical data is tabulated and shown as bar charts (preferred features), pie charts (proportions, for example colour choice) and line graphs or histograms (distribution of sizes), and averages and range summarise it.
Analysis: the mean and percentile spread of body measurements set the bag dimensions (designing for the appropriate range), and the most-requested features (mode of preferences) guide the specification; trends in the data justify decisions.
A strong answer distinguishes primary and secondary data, names suitable charts, and links the analysis (averages, spread, popularity) to specific design decisions, rather than describing data generically.
Related dot points
- Anthropometric data (measurements of the human body), the use of percentiles and percentile ranges, primary and secondary data sources, how to choose the appropriate percentile and design limits (design for the 5th to 95th percentile, design for the extreme, design for adjustability or the average), and applying anthropometric data to set product dimensions.
A focused answer to the Edexcel 9DT0 content on anthropometric data and percentiles, covering body measurements, percentile ranges, choosing design limits (5th to 95th, extreme, adjustable or average), and applying anthropometric data to set product dimensions.
- Calculating quantities of material and the cost of manufacture, including material and component costs, waste and yield, fixed and variable costs, unit cost, percentage profit and markup, break-even quantity, value added tax (VAT) and how costing informs pricing and the choice of process and scale.
A focused answer to the Edexcel 9DT0 content on costing and quantities, covering material and component costs, waste and yield, fixed and variable costs, unit cost, percentage profit and markup, break-even and VAT, and how costing informs pricing and process choice.
- Working with scale and ratio in drawings and models, reading and using scales (for example 1:2, 1:5, 1:10 and enlargement scales), calculating areas and volumes for material estimation, using trigonometry and geometry to find lengths and angles, surface area and capacity calculations, and converting between units in a design context.
A focused answer to the Edexcel 9DT0 content on scale, ratio and geometry, covering reading and using drawing scales, ratio and proportion, area and volume for material estimation, trigonometry for lengths and angles, surface area and capacity, and unit conversion.
- Testing and evaluating products against the specification and with users, methods of testing (function, durability, user trials, destructive and non-destructive testing), objective and subjective evaluation, and the role of standards and legislation (British and international standards, the BSI Kitemark, the CE and UKCA marks, key consumer and safety legislation) in ensuring products are safe and fit for purpose.
A focused answer to the Edexcel 9DT0 content on testing, evaluation and standards, covering testing methods and user trials, objective and subjective evaluation against the specification, and the role of standards and legislation (BSI Kitemark, CE and UKCA marks, consumer and safety law).
Sources & how we know this
- Pearson Edexcel A-Level Design and Technology: Product Design (9DT0) specification — Pearson Edexcel (2017)