📚 Year 8 AQA Economics: Case Study Practice | 案例分析实战演练
Welcome to your case study practice session for Year 8 AQA Economics. In this guide, we will follow the story of Sarah, a student who wants to start a small bracelet‑making business over the summer holidays. You will use key economic concepts — scarcity, opportunity cost, supply and demand, costs and revenue — to analyse her decisions. Work through each section, answer the questions in your head or on paper, and build your skills for tackling real economic problems.
欢迎来到 Year 8 AQA 经济学的案例分析实战演练。我们将跟随莎拉的故事，她是一名想在暑假开办一个手链小制作生意的大学生。你将运用稀缺性、机会成本、供求关系、成本和收益等关键经济学概念来分析她的决策。请逐节阅读并思考其中的问题，通过实战提高解决实际经济问题的能力。
1. Introducing the Case Study | 案例介绍：莎拉的手链生意
Sarah is a creative student with a limited budget. She has saved £20 from her pocket money and decides to make and sell friendship bracelets at the local park. Her aunt has offered to lend her a stall table for free, but Sarah must buy her own tools and materials. After researching online, she finds that a basic tool kit costs £5, and each bracelet requires colourful threads and beads that cost £2 per bracelet. Sarah estimates she can make one bracelet in 30 minutes. She plans to work up to 10 hours per week during the four‑week holiday.
莎拉是一个有创造力的学生，但预算有限。她从零花钱中攒了20英镑，决定在本地公园制作并售卖友谊手链。她的阿姨免费借给她一个摊位桌，但莎拉必须自己购买工具和材料。网上调查后她发现，一个基础工具包要5英镑，每根手链需要的彩线和珠子的成本是2英镑。莎拉估计她能在30分钟内制作一根手链。她计划在为期四周的假期中每周最多工作10小时。
Sarah wonders: how many bracelets should she make, at what price should she sell them, and can she really earn a profit? Let’s use economics to work through her business idea step by step.
莎拉心里在想：应该制作多少根手链、卖什么价格，她真的能赚到钱吗？让我们运用经济学的知识，一步一步分析她的商业点子。
2. Understanding Scarcity and Choice | 理解稀缺性与选择
Scarcity means that resources are limited while wants are unlimited. Sarah has a fixed amount of money (£20) and only a limited amount of time each week. She cannot buy all the materials she would like, nor can she make infinite bracelets. Because of scarcity, Sarah must make a choice about how to use her resources.
稀缺性意味着资源有限，而需求无限。莎拉拥有固定的金钱（20英镑），每周的时间也有限。她不可能买下所有想要的材料，也不可能制作无限多根手链。因为稀缺性的存在，莎拉必须就如何使用资源做出选择。
Economists say that every choice involves a trade‑off. For example, if Sarah uses her entire £20 to buy tools and materials for bracelets, she cannot also spend that money on cinema tickets or snacks. Time spent making bracelets is time she cannot spend swimming or reading. Recognising scarcity is the first step in making sensible economic decisions.
经济学家认为，每一个选择都伴随着权衡取舍。例如，莎拉如果把20英镑全部用来购买工具和材料，就不能再用这笔钱去买电影票或零食。用来制作手链的时间，就不能用来游泳或阅读。意识到稀缺性是做出理性经济决策的第一步。
3. Opportunity Cost in Decision Making | 决策中的机会成本
The opportunity cost of a choice is the value of the next best alternative that you give up. When Sarah decides to spend £5 on the tool kit, the opportunity cost might be the new book or the cinema trip she could have enjoyed with that money. When she spends two hours on a sunny afternoon making bracelets, the opportunity cost is the enjoyment she would have got from playing football with friends.
某个选择的机会成本，是你放弃的次优选项的价值。当莎拉决定花5英镑买工具包时，机会成本可能是她用这些钱能够享受的新书或电影。当她在一个晴朗的下午花两小时制作手链时，机会成本就是她与朋友踢球所能获得的快乐。
Understanding opportunity cost helps Sarah weigh up whether her bracelet business is truly worth the alternatives she leaves behind. If the satisfaction and profit from the business are greater than the opportunity cost, then the decision is economically sound. Otherwise, she might be better off doing something else.
理解机会成本能帮助莎拉权衡：她的手链生意是否真的值得让她放弃其他选项。如果生意带来的满足感和利润大于机会成本，那么从经济角度看这个决定就是合理的。否则，她或许还不如去做别的事。
4. Factors of Production in Sarah’s Business | 莎拉生意中的生产要素
Economists classify resources into four factors of production: land, labour, capital and enterprise. Sarah’s business uses all four: the ‘land’ is the stall space in the park (rented for free); labour is Sarah’s own time and effort; capital includes her tool kit, threads and the table; enterprise is Sarah’s idea and willingness to take the risk of starting a small venture.
经济学家把资源划分为四类生产要素：土地、劳动、资本和企业家才能。莎拉的生意使用了全部四种要素：‘土地’是公园里的摊位空间（免费使用）；劳动是莎拉自己的时间和精力投入；资本包括她的工具包、线和珠子，以及桌子；企业家才能则是莎拉的想法以及她愿意承担创业风险的精神。
Even a tiny business shows how these factors combine. Sarah will need to decide how much labour (hours) to supply, how to use her capital efficiently, and whether her enterprise skills can earn a reward — profit — for the risk she takes.
即便是一个微小的生意，也能展示这些要素是如何组合的。莎拉需要决定提供多少劳动（小时），如何高效使用她的资本，以及她的企业家才能能否为承担的风险赢得回报——也就是利润。
5. Supply and Demand Analysis | 供求分析
Demand tells us how many bracelets customers are willing and able to buy at different prices. Sarah notices that at £5 per bracelet, many children and teenagers in the park seem interested. However, if she raised the price to £8, some potential buyers might walk away. Demand is likely to be price‑sensitive.
需求告诉我们，消费者在不同价格下愿意且能够购买的手链数量。莎拉注意到，当每根手链定价5英镑时，公园里很多孩子和青少年都表现出兴趣。但如果她把价格提高到8英镑，一部分潜在顾客可能就会走开。手链的需求很可能对价格比较敏感。
lets a week (10 hours × 2 bracelets per hour) if she stays fully focused. Her supply depends on the price too: if she can sell each bracelet for £5, she has a strong incentive to produce more; at £2, she might not bother.
供给指的是莎拉愿意且能够制作的手链数量。在时间和材料有限的情况下，她如果全神贯注，每周最多能制作约20根手链（10小时×每小时两根）。她的供给也取决于价格：如果每根能卖5英镑，她就有很强的动力多做；如果只能卖2英镑，她可能就不愿费心了。
6. The Role of Price | 价格的作用
The price of a bracelet acts as a signal to both buyers and sellers. When Sarah sets the price at £5, she sends a message about the value of her handmade product. Price also helps balance supply and demand. If she prices too high, a surplus of unsold bracelets could pile up. If she prices too low, she might face a shortage — more customers want bracelets than she can produce, but she earns very little per sale.
手链的价格对买卖双方都起信号作用。莎拉把价格定为5英镑时，就在向顾客传递关于她手工作品价值的信息。价格也有助于平衡供求。如果定价过高，可能出现卖不掉的手链积压（剩余）。如果定价过低，则可能面临短缺——想买的顾客多过她能生产的数量，但她每笔买卖挣得很少。
Sarah experiments: she starts at £5 and observes how many bracelets she sells each day. She discovers that at £5 she can reliably sell 6 bracelets per afternoon, which matches well with the number she can comfortably make. The price mechanism has guided her towards an efficient allocation of resources.
莎拉进行了尝试：她以5英镑起卖，观察每天能卖出多少根手链。她发现在5英镑的价格下，每个下午可以稳定卖出6根，这刚好与她能轻松制作的量相匹配。价格机制就这样引导她把资源分配到最有效的位置。
7. Calculating Costs, Revenue and Profit | 计算成本、收入与利润
To know whether Sarah is really earning money, we must understand three key terms. Total costs include all expenses: the fixed cost of the tool kit (£5) and the variable cost of materials per bracelet (£2). Total revenue is the money she receives from sales. Profit is the difference between total revenue and total cost.
要知道莎拉是否真的在赚钱，我们必须理解三个关键术语。总成本包括所有支出：工具包的固定成本（5英镑）和每根手链的可变材料成本（2英镑）。总收入是她从销售中获得的货款。利润就是总收入与总成本之差。
Profit = Total Revenue − Total Cost
利润 = 总收入 − 总成本
Suppose Sarah buys the tool kit and enough materials to make 7 bracelets (spending £5 + 7 × £2 = £19, leaving £1 leftover). If she sells all 7 at £5 each, her total revenue is £35. Total cost is £19. Her profit is £35 − £19 = £16. That shows a healthy return on her small investment.
假设莎拉购买了工具包以及足够制作7根手链的材料（花费5 + 7×2 = 19英镑，还剩1英镑）。如果她以每根5英镑的价格全部卖出，总收入是35英镑。总成本为19英镑。她的利润是35 − 19 = 16英镑。这说明她的小投资获得了不错的回报。
We can put these numbers in a simple table to organise her finances.
我们可以把这些数字放入一个简单的表格，便于整理她的财务数据。
| Fixed cost (tools) | £5 |
| Variable cost (£2 × 7) | £14 |
| Total cost | £19 |
| Revenue (£5 × 7) | £35 |
| Profit | £16 |
Keeping track of costs and revenues like this is essential for any business, no matter how small.
像这样跟踪成本和收入，对任何企业——不管多小——都至关重要。
8. Break‑even Analysis | 盈亏平衡分析
The break‑even point is the number of units a business must sell to cover all its costs exactly, so it makes neither a profit nor a loss. Sarah’s fixed cost is £5. Each bracelet sells for £5 and has a variable cost of £2, so each one sold contributes £3 towards the fixed cost. This is called the contribution per unit.
盈亏平衡点是指企业为了刚好覆盖全部成本，既不盈利也不亏损而必须售出的产品数量。莎拉的固定成本是5英镑。每根手链售价5英镑，可变成本为2英镑，因此每卖掉一根手链就能为固定成本贡献3英镑。这叫做单位边际贡献。
Break‑even point (units) = Fixed Costs ÷ (Selling Price per unit − Variable Cost per unit)
盈亏平衡点（单位） = 固定成本 ÷ (单位售价 − 单位可变成本)
Using Sarah’s numbers: £5 ÷ (£5 − £2) = £5 ÷ £3 ≈ 1.67. Since she can’t sell a fraction of a bracelet, the break‑ she has covered her fixed costs, and any additional bracelet sold generates pure profit of £3 each.
代入莎拉的数据：5 ÷ (5 − 2) = 5 ÷ 3 ≈ 1.67。由于不能卖出分数根手链，盈亏平衡点就是2根手链。莎拉只要卖出2根手链，就能覆盖固定成本，此后每多卖一根就能带来3英镑的纯利润。
Break‑even analysis is a powerful tool for deciding whether a business idea is worth pursuing. If Sarah thought she could only sell one bracelet, she would expect a loss. Knowing she can easily sell at least two gives her confidence.
盈亏平衡分析是判断一个商业想法是否值得尝试的有力工具。如果莎拉认为自己只能卖出一根手链，她将面临亏损。得知自己轻松就能卖出至少两根，就让她充满信心。
9. Budgeting and Resource Allocation | 预算与资源配置
A budget is a plan for how to spend limited money. Sarah starts with £20. She must decide how to allocate this between the tool kit and materials. If she spends £5 on tools, she has £15 left. With each bracelet material pack costing £2, she can buy a maximum of 7 packs (£14), leaving £1 unused. This is a trade‑off: should she buy 7 material packs and keep some cash spare, or find a cheaper tool kit to free up money for more materials?
预算是关于如何使用有限资金的计划。莎拉最初有20英镑。她必须决定如何在工具包和材料之间分配这笔钱。如果她花5英镑买工具，还剩下15英镑。每份手链材料包花费2英镑，她最多能买7份（14英镑），余下1英镑。这是一种权衡：她应该买7份材料并保留一点现金，还是找一个更便宜的工具包，省出钱来购买更多材料？
Good budgeting helps Sarah avoid running out of materials early or spending too much on fixed items. She decides to stick with the £5 tool kit because it is good quality, and to purchase materials for 7 bracelets as her first batch. After she sells those, she can use some of the revenue to buy more materials, effectively reinvesting profit.
良好的预算帮助莎拉避免过早用光材料或在固定物品上花费过多。她决定继续选用质量不错的5英镑工具包，先购买7根手链的材料作为第一批产品。等卖掉这些之后，就可以用一部分收入购买更多材料，实际上是在进行利润再投资。
This is a classic example of resource allocation: making deliberate choices about where scarce funds go, so that the business can survive and grow.
这就是资源配置的经典例子：对稀缺资金的使用做出审慎选择，使生意能够生存并增长。
10. Market Research and Consumer Preferences | 市场调研与消费者偏好
Before launching her stall, Sarah carried out simple market research. She asked her friends and neighbours what colours and styles they liked, and she observed what similar bracelets sold for online. This helped her understand consumer preferences — the tastes and wishes of potential buyers.
在摊位开张之前，莎拉进行了简单的市场调研。她询问了朋友和邻居喜欢的颜色和款式，还观察了网上类似的手链售价。这帮她了解了消费者偏好——潜在买家的口味和愿望。
Market research reduces the risk of producing something nobody wants. If Sarah had made only blue bracelets but her customers wanted rainbow colours, she would be left with unsold stock. By listening to consumers, she designed a range of colourful bracelets that appealed to many tastes, increasing the likelihood of strong demand.
市场调研能降低生产出无人问津产品的风险。如果莎拉只制作蓝色手链，而顾客们想要彩虹色的，那她就会剩下卖不掉的库存。通过倾听消费者的意见，她设计了多种颜色的手链系列，迎合了不同的喜好，从而增加了强需求的概率。
Even a small‑scale business benefits greatly from understanding its customers. Sarah also noted that most people were willing to pay £4‑£6 for a handmade bracelet, confirming her £5 price point was sensible.
即使是一个小规模的生意，了解顾客也会带来极大的好处。莎拉还注意到多数人愿意为手工手链支付4至6英镑，这证实她5英镑的定价点是合理的。
11. External Factors Affecting the Business | 影响生意的外部因素
External factors are things outside Sarah’s control that can influence her business. The weather is a big one: a rainy day means fewer people in the park and lower sales. Another factor is competition. If another student starts selling friendship bracelets at a lower price, Sarah may lose customers or have to reduce her own price.
外部因素是莎拉无法控制，但会影响她生意的事情。天气是一个重要的因素：下雨天公园里人少，销量就会下降。另一个因素是竞争。如果另一个学生开始以更低的价格售卖友谊手链，莎拉可能会流失顾客，或者不得不降低自己的价格。
Changes in the cost of materials also matter. If the price of threads or beads rises from £2 to £3 per bracelet, Sarah’s variable cost increases, reducing her profit unless she raises her selling price. Economic conditions, such as parents having less pocket money to give, could also reduce customers’ willingness to spend.
材料成本的变化也很重要。如果每根手链所需线、珠的成本从2英镑涨到3英镑，莎拉的可变成本就会上升，除非她提高卖价，否则利润会减少。经济状况，比如家长们给的零花钱变少，也可能降低顾客的消费意愿。
Good entrepreneurs like Sarah learn to anticipate and respond to these external factors. She could, for example, offer a ‘rainy day discount’ to attract the few visitors in the park, or differentiate her bracelets with unique designs that competitors cannot easily copy.
像莎拉这样的优秀创业者会学着预判并应对外部因素。例如，她可以推出‘雨天折扣’来吸引公园里少数游客，或者用独特的设计让自己的手链脱颖而出，让竞争者难以轻易模仿。
12. Evaluation and Key Takeaways | 评估与关键要点
Sarah’s bracelet business is a simple but powerful way to see economics in action. By recognising scarcity, she made careful choices. Calculating opportunity cost reminded her of what she was giving up. Understanding supply and demand helped her set a sensible price, and by tracking costs and revenue she could see her profit clearly. Together, these tools allowed Sarah to turn a £20 budget into a rewarding summer activity.
莎拉的手链生意虽然简单，却是观察经济学在现实中运作的一个有力例子。通过认识到稀缺性，她做出了谨慎的选择。计算机会成本让她想起自己放弃了什么。理解供求关系帮她定出了合理的价格，而跟踪成本和收入让她清楚地看到了利润。这些工具综合起来，让莎拉把20英镑的预算变成了一项有回报的暑期活动。
When you face your own economic case studies — whether about a shop, a tourist attraction or a country’s budget — remember the same step‑by‑step approach: identify the scarce resources, consider opportunity costs, analyse supply and demand, calculate costs and revenues, and always evaluate the external influences at play.
当你在面对自己的经济案例分析时——无论是关于一家商店、一个旅游景点还是一国的预算——请记住同样的循序渐进的思路：找出稀缺资源，考虑机会成本，分析供求，计算成本和收入，并始终评估外部因素的影响。
Economics is not just about money; it is a way of thinking that helps you make better decisions in everyday life. Use these skills to practise with other case studies and build your confidence for the AQA Economics course.
经济学不只是关于金钱；它是一种思维方式，能帮助你在日常生活中做出更好的决定。运用这些技巧练习其他案例，为AQA经济学课程积累信心。
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