📚 Year 11 SQA Statistics: Case Study Practical Exercises | SQA 统计：案例分析实战演练
This article takes you through a complete SQA Statistics case study, linking screen time and sleep patterns among 20 Year 11 students. We will collect, organise, visualise, analyse and interpret data step by step, covering the key skills required for your SQA exam. From frequency tables to standard deviation, from tree diagrams to regression lines, this hands-on revision guide will sharpen your statistical reasoning and data-handling confidence.
本文带您完整演练一个 SQA 统计案例，分析 20 名 Year 11 学生屏幕使用时间与睡眠模式的关联。我们将逐步收集、整理、可视化、分析和解释数据，涵盖 SQA 考试所有关键技能。从频率分布表到标准差，从树形图到回归直线，这份实战复习指南将显著提升您的统计推理能力和数据处理自信。
1. Case Overview: Screen Time vs Sleep | 案例概述：屏幕时间与睡眠
A group of 20 S4 students recorded their daily mobile phone screen time (in hours) and their average nightly sleep duration (in hours) over one week. The goal is to investigate whether there is a relationship between screen time and sleep, and to practise the full SQA statistical enquiry cycle: specifying the problem, collecting data, processing and presenting information, and interpreting results.
20 名 S4 学生记录了一周内每日手机屏幕使用时间（小时）和平均夜间睡眠时长（小时）。目标是探究屏幕时间与睡眠之间是否存在关联，并完整演练 SQA 统计探究周期：明确问题、收集数据、处理与呈现信息、解释结果。
The raw data pairs (screen time X, sleep Y) are shown below. We will use this dataset throughout all sections.
原始数据对（屏幕时间 X，睡眠 Y）如下，整篇文章都将使用该数据集。
| Student | X (h) | Y (h) | Student | X (h) | Y (h) |
|---|---|---|---|---|---|
| 1 | 1 | 9 | 11 | 5 | 7 |
| 2 | 2 | 8.5 | 12 | 5 | 6 |
| 3 | 2 | 9 | 13 | 5 | 6.5 |
| 4 | 3 | 8 | 14 | 6 | 6 |
| 5 | 3 | 7.5 | 15 | 6 | 5.5 |
| 6 | 3 | 8 | 16 | 7 | 6 |
| 7 | 4 | 7 | 17 | 7 | 5 |
| 8 | 4 | 7.5 | 18 | 8 | 5 |
| 9 | 4 | 7 | 19 | 9 | 4.5 |
| 10 | 4 | 6.5 | 20 | 10 | 4 |
2. Organising Data: Frequency Tables | 数据整理：频率分布表
lps us see the distribution shape and prepare for drawing a histogram. We choose classes 0 – 2, 2 – 4, 4 – 6, 6 – 8 and 8 – 10, taking care to define boundaries clearly (e.g. 2 – 4 means 2 ≤ x < 4).
为汇总屏幕时间变量，我们首先将 X 值分组到等宽区间。频率分布表能帮助我们看到分布形态并为绘制直方图做准备。我们选择区间 0–2、2–4、4–6、6–8
Published by TutorHao | Year 11 统计 Revision Series | aleveler.com
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