📚 Year 9 CCEA Statistics: Case Study Practical Exercises | Year 9 CCEA 统计：案例分析实战演练
In this article, we explore how to carry out a statistical case study from start to finish. You will learn to define a question, collect data, summarise findings, and draw conclusions, all tailored to the CCEA Year 9 Statistics curriculum. Case studies bring numbers to life — they help you see how statistics can solve real problems.
在这篇文章中，我们将从头到尾探索如何进行一次统计案例研究。你将学会定义问题、收集数据、总结发现并得出结论，所有内容均围绕CCEA Year 9统计课程设计。案例研究让数字变得生动——它们帮助你看到统计如何解决实际问题。
1. What is a Statistical Case Study? | 什么是统计案例研究？
A statistical case study is an investigation that uses data to answer a specific question. It follows a structured process: Problem, Plan, Data, Analysis, Conclusion (often called the PPDAC cycle). At Year 9 level, this means picking a topic you care about, gathering evidence, and making informed judgements.
统计案例研究是一种利用数据回答特定问题的调查研究。它遵循一个结构化的过程：问题、计划、数据、分析、结论（通常称为PPDAC循环）。在Year 9阶段，这意味着选择一个你关心的话题，收集证据，并做出有依据的判断。
2. Defining a Clear Research Question | 定义明确的研究问题
Every case study begins with a well-defined question. It should be focused and measurable. For example, ‘How happy are Year 9 students with the school canteen?’ is more precise than ‘Is the canteen good?’. A good question guides your entire project and ensures you collect relevant data.
每个案例研究都始于一个明确的问题。问题应该重点突出、可测量。例如，‘Year 9学生对学校食堂的满意度如何？’就比‘食堂好吗？’更精确。一个好问题能指导你的整个项目，确保你收集到相关数据。
3. Planning Data Collection | 规划数据收集
Once the question is set, decide how to gather information. You can use primary data (collected yourself) or secondary data (from existing sources). Primary data might come from questionnaires, interviews, or observations. Choose a method that suits your question and resources. Always consider ethics — keep responses anonymous if needed.
问题确定后，决定如何收集信息。你可以使用一手数据（自己收集）或二手数据（来自现有资料）。一手数据可以来自问卷、访谈或观察。选择适合你的问题和资源的方法。始终考虑伦理问题——必要时对回答匿名处理。
4. Designing Effective Questionnaires | 设计有效的问卷
A questionnaire is a common tool in Year 9 case studies. Use a mix of closed questions (yes/no, multiple choice, rating scales) and one or two open questions for detailed feedback. Avoid leading or biased wording — ask neutrally. Pilot your questions with a friend to spot any confusion.
问卷是Year 9案例研究中的常用工具。混合使用封闭式问题（是非题、选择题、评分量表）和一两个开放性问题以获取详细反馈。避免引导性或偏颇的措辞——中性提问。请朋友试填一次，找出任何不清楚的地方。
5. Choosing the Right Sampling Method | 选择合适的抽样方法
You cannot usually survey everyone, so you need a sample. Random sampling gives every person an equal chance, reducing bias. Stratified sampling divides the population into groups and samples proportionally. Convenience sampling (e.g., asking your friends) is easy but may not represent the whole year group. Think carefully about how sample size affects the reliability of your findings.
你通常无法调查所有人，因此需要抽样。随机抽样给每个人平等机会，减少偏差。分层抽样将总体分组并按比例抽样。便利抽样（如询问你的朋友）简单但可能无法代表整个年级。仔细思考样本大小如何影响结论的可靠性。
6. Organising and Cleaning Data | 数据整理与清洗
Raw data needs to be organised before analysis. Use tally charts and frequency tables to count responses. Check for errors — a rating of ‘6’ on a 1–5 scale is impossible and must be removed or corrected. Clean data makes your later calculations and graphs accurate.
原始数据在分析前需要整理。使用计数符号和频数表来统计回答。检查错误——1–5分量表中出现‘6’分是不可能的，必须删除或纠正。干净的数据能确保后续计算和图表的准确性。
7. Visualising Data with Graphs | 用图表直观呈现数据
Graphs help you see patterns at a glance. For categorical data, use bar charts or pie charts. For numerical satisfaction scores, a bar chart showing frequencies or a dot plot works well. Line graphs show changes over time. Always label axes, give a title, and keep the scale even. Choose the graph type that best highlights your message.
图表帮助你一目了然地看到模式。对于类别数据，使用柱状图或饼图。对于数值型满意度评分，用显示频数的柱状图或点阵图效果较好。折线图显示随时间的变化。始终标注坐标轴、给出标题并保持刻度均匀。选择最能突出你要传达的信息的图表类型。
8. Calculating Summary Statistics | 计算概括统计量
Numbers summarise the centre and spread of your data. The mean (x̄) is the arithmetic average. The median is the middle value when data is ordered. The mode is the most frequent value. The range shows the difference between the highest and lowest values. For a set of satisfaction scores out of 5, you might compute these to capture the typical student experience.
数字概括了数据的中心和离散程度。平均数（均值）是算术平均值。中位数是数据排序后的中间值。众数是出现频率最高的值。极差显示最大值与最小值之差。对于一组满分5分的满意度评分，你可以计算这些统计量来描述典型的学生体验。
Mean = (sum of all values) / (number of values)
平均数 = 所有数值之和 / 数值个数
9. Interpreting Your Findings | 解读你的发现
Look at your graphs and summary statistics together. What do they tell you? If the mean canteen satisfaction is 2.95 out of 5, and the median is 3, the typical student feels neutral or slightly dissatisfied. Compare groups — maybe Year 9 boys and girls gave different average ratings. Link your interpretation directly back to the original research question.
结合图表和概括统计量一起看。它们告诉你什么？如果食堂满意度平均分为2.95（满分5分），中位数为3，则典型学生感觉一般或略微不满意。比较不同组别——可能Year 9男生和女生给出的平均评分不同。将你的解读直接关联回最初的研究问题。
10. Drawing Conclusions and Recognising Limitations | 得出结论并认识局限性
Your conclusion should answer the research question clearly — for instance, ‘Year 9 students are not very satisfied with the canteen, and the most common suggestion is more variety.’ Always discuss limitations: sample size, potential bias if you only surveyed your class, or poorly worded questions. Honest reflection makes your study stronger.
你的结论应当清晰地回答研究问题——例如，‘Year 9学生对食堂不太满意，最常见的建议是增加菜品多样性。’始终讨论局限性：样本大小、如果你只调查了自己班级可能带来的偏差、或措辞不当的问题。诚实的反思能让你的研究更有说服力。
11. Presenting Your Case Study Report | 展示你的案例研究报告
A good report has a clear structure: title, introduction (question and why it matters), method (data collection and sampling), results (graphs and statistics), analysis (interpretation), and conclusion with limitations. Use headings, bullet points for key findings, and neat graphs. Keep your language simple and objective.
一份好的报告结构清晰：标题、引言（问题及意义）、方法（数据收集和抽样）、结果（图表和统计量）、分析（解读）以及含局限性的结论。使用标题、要点列出关键发现，以及整洁的图表。保持语言简洁客观。
12. Real-World Case Study: Canteen Satisfaction Survey | 真实案例研究：食堂满意度调查
Let’s walk through a complete example. A Year 9 student wanted to investigate: ‘How satisfied are Year 9 students with the school canteen?’ She designed a short questionnaire asking for a satisfaction score from 1 (very unsatisfied) to 5 (very satisfied) and an optional comment. She used a random sample of 20 Year 9 students from the year group list.
让我们走过一个完整的例子。一位Year 9学生想要研究：‘Year 9学生对学校食堂的满意度如何？’她设计了一份简短问卷，要求给出从1分（非常不满意）到5分（非常满意）的满意度评分，并可选评论。她从年级名单中随机抽取了20名Year 9学生作为样本。
After collecting the responses, she organised the raw data into a frequency table:
收集回答后，她将原始数据整理成频数表：
| Score (x) | Frequency (f) |
|---|---|
| 1 | 2 |
| 2 | 5 |
| 3 | 7 |
| 4 | 4 |
| 5 | 2 |
She then calculated the summary statistics:
然后她计算了概括统计量：
Mode: 3 (occurs 7 times)
众数：3（出现7次）
Median: With 20 values, the median is the average of the 10th and 11th
Published by TutorHao | Year 9 统计 Revision Series | aleveler.com
更多咨询请联系16621398022（同微信）
屏轩国际教育cambridge primary/secondary checkpoint, cat4, ukiset,ukcat,igcse,alevel,PAT,STEP,MAT, ibdp,ap,ssat,sat,sat2课程辅导，国外大学本科硕士研究生博士课程论文辅导