Year 10 SQA Statistics: Case Study in Action | 十年级SQA统计：案例分析实战演练

📚 Year 10 SQA Statistics: Case Study in Action | 十年级SQA统计：案例分析实战演练

In this article, we will work through a complete statistical investigation based on a survey carried out in a secondary school canteen. The aim is to demonstrate how the key tools of descriptive statistics – collecting data, organising it into tables, drawing charts, calculating averages and measures of spread, exploring correlation and probability – come together in a real-world context. Each step mirrors the type of tasks you might meet in your SQA Statistics course, building your confidence in handling data from start to finish.

本文将通过一项中学食堂调查，完整展示一次统计研究的过程。目的在于演示如何将描述性统计的核心工具——数据收集、整理成表、绘制图表、计算平均数与离散量数、探索相关性与概率——融合在一个真实情境中。每个步骤都与SQA统计课程中可能遇到的题目相似，帮助你从头到尾自信地处理数据。

1. Case Background: The School Canteen Survey | 案例背景：学校食堂调查

The school canteen manager wants to improve the lunch service. She decides to investigate three aspects: which lunch options are most popular, how much money students typically spend each day, and whether the amount spent is related to how satisfied students feel with their meal. A survey is designed to collect data from a random sample of 20 students across different year groups. The questions asked are: ‘Which lunch choice did you make today?’, ‘How much did you spend (to the nearest 10p)?’ and ‘On a scale of 1 (very dissatisfied) to 5 (very satisfied), how would you rate your meal?’.

学校食堂经理想改善午餐服务。她决定调查三个方面：哪种午餐选择最受欢迎、学生通常每天花费多少钱，以及花费金额是否与学生对其餐食的满意度有关。调查设计好之后，从不同年级随机抽取了20名学生作为样本。提出的问题是：“你今天选择了哪种午餐？”“你花了多少钱（精确到10便士）？”以及“如果用1分（非常不满意）到5分（非常满意）来打分，你会给这顿饭打几分？”

2. Data Collection Methods | 数据收集方法

Data were collected through a short paper questionnaire handed out as students left the canteen. Using a simple random sample ensures that every student has an equal chance of being selected, which reduces bias. The responses were recorded in a spreadsheet, with each student assigned an ID number to preserve anonymity. The three variables are: lunch choice (categorical), amount spent (continuous numerical), and satisfaction score (discrete numerical). All entries were checked for obvious errors, such as missing values or unrealistic spending.

数据通过在学生离开食堂时分发简短纸质问卷收集。采用简单随机抽样可以确保每位学生都有同等被选中的机会，从而减少偏差。回答内容被记录在电子表格中，每位学生都分配了识别编号以便匿名保护。三个变量分别是：午餐选择（分类变量）、花费金额（连续数值变量）和满意度打分（离散数值变量）。所有录入内容都经过了明显错误的检查，例如缺失值或不合理的花费金额。

The raw data for the 20 students are shown in the table below. Each row contains a student’s lunch choice, spend in pounds, and satisfaction rating. This dataset will form the basis for all our subsequent analyses.

20名学生的原始数据如下表所示。每一行包含一名学生的午餐选择、花费金额（以英镑为单位）以及满意度评分。该数据集将作为我们所有后续分析的基础。