📚 Key Points for Experimental/Practical Assessment in Year 11 WJEC Psychology | WJEC 心理学 Year 11 实验/实践考核要点
This guide breaks down the essential knowledge and skills you need to excel in the practical investigation component of the WJEC GCSE Psychology course. Understanding how to design, conduct, analyse, and evaluate a piece of research is central to achieving a high mark, and these principles also appear across the written examination papers. Here we will explore the key concepts step by step, from formulating hypotheses to writing your final report.
本指南将拆解你在 WJEC GCSE 心理学课程实践调查部分取得优异成绩所需的核心知识与技能。理解如何设计、实施、分析和评估一项研究是获得高分的核心，这些原则也会出现在笔试考卷中。我们将逐步探索关键概念，从提出假设直到撰写最终报告。
1. Understanding the Experimental Method | 理解实验方法
The experimental method involves manipulating an independent variable (IV) to observe its effect on a dependent variable (DV) while keeping all other conditions controlled. In WJEC Psychology, you need to recognise that this is the most powerful way to establish cause-and-effect relationships. Your own practical task may be an experiment, but the same logic applies to any investigation where you gather primary data.
实验法涉及操纵自变量（IV）以观察其对因变量（DV）的影响，同时保持所有其他条件受控。在 WJEC 心理学中，你需要认识到这是建立因果关系最有力的方式。你自己的实践任务可能是一项实验，但同样的逻辑适用于任何收集一手数据的调查。
For example, you might investigate whether listening to background music affects concentration. Here, the presence or type of music is manipulated, and a test of concentration is measured. A true experiment requires careful control of potential confounding variables so that any change in the DV can be confidently attributed to the IV.
例如，你可能会研究听背景音乐是否影响注意力。在这里，操纵的是音乐的有无或类型，并测量注意力测试成绩。一项真正的实验需要仔细控制潜在的混淆变量，以便任何因变量的变化都可以确信地归因于自变量。
2. Formulating Hypotheses | 提出假设
A hypothesis is a precise, testable prediction about the outcome of your investigation. You will usually write both an alternative hypothesis and a null hypothesis. The alternative hypothesis (H₁) predicts a significant effect or difference, while the null hypothesis (H₀) states that there will be no significant effect or difference, and any observed change is due to chance.
假设是一个精确的、可检验的关于调查结果的预测。你通常需要同时写出备择假设和零假设。备择假设（H₁）预测存在显著效应或差异，而零假设（H₀）则陈述不存在显著效应或差异，任何观察到的变化都是由偶然因素造成的。
Alternative hypotheses can be directional, such as 'Participants who drink caffeine will score higher on a memory test than those who do not'. They can also be non-directional, e.g. 'There will be a difference in memory test scores between participants who have caffeine and those who have none'. WJEC examiners expect you to choose the appropriate type based on previous research or the task instructions.
备择假设可以是方向性的，例如“饮用咖啡因的参与者在记忆测试中的得分将高于未饮用咖啡因的参与者”。也可以是非方向性的，例如“饮用咖啡因与未饮用咖啡因的参与者在记忆测试得分上存在差异”。WJEC 考官期望你根据先前的研究或任务指导选择合适的类型。
3. Identifying Independent and Dependent Variables | 识别自变量与因变量
The independent variable (IV) is the factor you deliberately change or manipulate. It must have at least two conditions, such as an experimental condition and a control condition. The dependent variable (DV) is the factor you measure to see if the IV has had an effect. Operationalising your variables clearly is essential — this means defining them in a way that allows them to be manipulated or measured precisely.
自变量（IV）是你有意改变或操纵的因素。它必须至少包含两个条件，例如实验条件和控制条件。因变量（DV）是你为了观察自变量是否产生影响而测量的因素。清晰地操作化你的变量至关重要——这意味着以允许精确操纵或测量的方式定义它们。
For instance, if your aim is to study the effect of exercise on mood, you might operationalise the IV as '30 minutes of moderate running' versus '30 minutes of sitting quietly'. The DV could be operationalised as 'score on a standardised mood questionnaire out of 50'. Without clear operationalisation, your study cannot be replicated and lacks validity.
例如，如果你的目的是研究锻炼对情绪的影响，你可以将自变量操作化为“30分钟中等强度的跑步”对比“30分钟安静地坐着”。因变量可以被操作化为“标准化情绪问卷得分（满分50分）”。没有清晰的操作化，你的研究就无法被重复，且缺乏效度。
A simple table can help you keep track:
| Concept | Example for a study on background noise and reading speed |
| Independent Variable | Level of background noise (quiet room vs. 60 dB traffic noise) |
| Dependent Variable | Reading speed in words per minute on a standard passage |
一个简单的表格可以帮助你理清思路：
| 概念 | 背景噪音与阅读速度研究的例子 |
| 自变量 | 背景噪音水平（安静房间 vs. 60分贝交通噪音） |
| 因变量 | 阅读标准段落的速度（每分钟单词数） |
4. Controlling Extraneous Variables | 控制额外变量
Extraneous variables are any factors other than the IV that could influence the DV. If they are not controlled, they can become confounding variables, making it impossible to conclude that the IV alone caused any observed change. You must identify potential extraneous variables in your practical and explain how you will control them.
额外变量是除了自变量之外任何可能影响因变量的因素。如果不加以控制，它们就会变成混淆变量，使得你无法得出仅由自变量引起任何观察到的变化的结论。你必须在实践过程中识别潜在的额外变量，并解释你将如何控制它们。
Common extraneous variables include participant variables (age, gender, prior experience), situational variables (room temperature, time of day, noise), and experimenter effects (cues given by the researcher). Standardisation of the procedure and instructions is the most basic form of control. Using a laboratory setting, random assignment, or counterbalancing can further reduce threats.
常见的额外变量包括参与者变量（年龄、性别、先前经验）、情境变量（室温、一天中的时间、噪音）和实验者效应（研究者给出的暗示）。程序和指导语的标准化是最基本的控制形式。使用实验室环境、随机分配或平衡设计可以进一步减少威胁。
- Use standardised instructions read from a script to ensure all participants receive the same information.
- Keep the physical environment constant, e.g. same room, lighting, and seating arrangement for all conditions.
- Use random allocation to distribute participant characteristics evenly across experimental conditions in independent groups designs.
- 使用从脚本宣读的标准化指导语，确保所有参与者获得相同的信息。
- 保持物理环境恒定，例如所有条件下使用相同的房间、照明和座位安排。
- 在独立组设计中采用随机分配，使参与者特征均匀分布到各个实验条件中。
5. Experimental Designs | 实验设计
Experimental design refers to how participants are allocated to the different conditions of the IV. The three main designs are independent groups, repeated measures, and matched pairs. Each has strengths and weaknesses that you must be able to discuss in your evaluation.
实验设计指的是参与者如何被分配到自变量的不同条件。三种主要设计是独立组设计、重复测量设计和配对设计。每种设计都有其优缺点，你必须能在评估中加以讨论。
In an independent groups design, different participants take part in each condition. This avoids order effects, but participant variables may differ between groups. Repeated measures uses the same participants in all conditions, which eliminates individual differences but can lead to order effects such as practice or fatigue. Matched pairs uses different but similar participants, matched on key characteristics; it reduces participant variables but is time-consuming.
在独立组设计中，不同的参与者分别参加每个实验条件。这种方式避免了顺序效应，但各组之间的参与者变量可能不同。重复测量设计在所有条件下使用相同的参与者，消除了个体差异，但可能导致练习效应或疲劳等顺序效应。配对设计使用不同但相似的参与者，依据关键特征进行匹配；它减少了参与者变量，但非常耗时。
When planning a practical for WJEC, you should select a design that suits your research question and acknowledge its limitations. For example, if you use repeated measures, you should include counterbalancing — half the participants do condition A then B, the other half do B then A — to minimise order effects.
在为 WJEC 规划实践时，你应选择适合研究问题的设计，并承认其局限性。例如，如果你采用重复测量设计，就应引入平衡法——一半参与者先完成条件 A 后完成条件 B，另一半则先 B 后 A——以最大限度减少顺序效应。
6. Sampling Methods | 抽样方法
The sample is the group of people who take part in your study, drawn from a target population. The method you use to select your sample directly affects how far you can generalise your findings. WJEC expects you to name the sampling method and justify it in relation to representativeness and potential bias.
样本是参与研究的一组人，他们来自目标总体。你选择样本的方法直接影响到你能将研究结论推广到多大范围。WJEC 期望你说出抽样方法的名称，并从代表性和潜在偏差的角度为其提供理由。
- Random sampling: every member of the target population has an equal chance of being chosen (e.g. drawing names from a hat). It reduces researcher bias but is often impractical.
- Opportunity sampling: selecting people who are readily available and willing to participate. It is quick and convenient, but the sample may be unrepresentative.
- Systematic sampling: selecting every nth person from a list. This can produce a reasonably representative sample if the list is ordered randomly.
- Stratified sampling: the population is divided into subgroups (strata) and participants are selected proportionally from each. This yields a highly representative sample but requires detailed population information.
- 随机抽样：目标总体中的每个成员都有相等的机会被选中（例如从帽子中抽签）。减少了研究者偏差，但通常不切实际。
- 机会抽样：选择顺手可得且愿意参与的个体。快捷方便，但样本可能不具有代表性。
- 系统抽样：从名单中每隔第 n 个人选择一个。如果名单是随机排序的，可以产生相当有代表性的样本。
- 分层抽样：将总体划分为子群（层），然后按比例从每一层中选取参与者。可产生高度代表性的样本，但需要详细的总体信息。
7. Ethical Considerations | 伦理考量
All psychological investigations must follow strict ethical guidelines, and for your WJEC practical this is a key assessment point. The British Psychological Society (BPS) sets out principles including informed consent, the right to withdraw, protection from harm, confidentiality, and avoidance of deception unless absolutely necessary and followed by debriefing.
所有心理学调查都必须遵循严格的伦理准则，这对你的 WJEC 实践而言是一个关键的评估要点。英国心理学会（BPS）制定了若干原则，包括知情同意、退出权、免受伤害、保密，以及除非绝对必要且随后进行事后解释，否则应避免欺骗。
Informed consent means that participants must know the general purpose of the study and what their participation involves before they agree to take part. For under-16s, you must also obtain parental consent. You should make it clear that participants can withdraw at any time without giving a reason, and their data will be removed. All personal data must be kept anonymous, usually by using participant numbers instead of names.
知情同意意味着参与者在同意参加之前必须了解研究的大致目的以及参与的内容。对于 16 岁以下参与者，你还必须获得父母同意。你要清楚说明参与者可以随时退出且无需给出理由，他们的数据将被删除。所有个人数据必须保持匿名，通常使用参与者编号而非姓名。
Before you begin your investigation, you should complete an ethical checklist and have it approved by your teacher. After the study, debrief participants fully — explain the true aims, check for any discomfort, and provide contact details for further support if needed.
在开始调查之前，你应该填写一份伦理清单并由老师批准。研究结束后，要对参与者进行充分的事后解释——说明真实目的，检查是否存在任何不适，并在需要时提供进一步支持的联系方式。
8. Data Collection and Descriptive Statistics | 数据收集与描述统计
Once you have conducted your practical, you will have raw data that needs to be summarised and described. WJEC expects you to be comfortable with descriptive statistics: measures of central tendency and measures of dispersion. You must be able to calculate and interpret the mean, median, mode, and range.
一旦你完成了实践，你将拥有需要总结和描述的原始数据。WJEC 期望你熟练掌握描述统计：集中趋势量数和离散程度量数。你必须能够计算和解释平均数、中位数、众数和极差。
- The mean is the arithmetic average. For a set of scores, it is calculated as Σx / n, where Σx is the sum of all scores and n is the number of scores.
- The median is the middle value when scores are arranged in order. It is not affected by extreme scores.
- The mode is the most frequently occurring score.
- The range is a simple measure of dispersion: highest score – lowest score. A larger range indicates greater variability.
- 平均数是算术平均值。对于一组分数，计算公式为 Σx / n，其中 Σx 是所有分数之和，n 是分数的个数。
- 中位数是将分数按顺序排列后位于中间的值。它不受极端分数的影响。
- 众数是出现频率最高的分数。
- 极差是简单的离散程度量数：最高分数 – 最低分数。极差越大说明变异性越大。
be (7+9+8+10+12+7)/6 = 53/6 ≈ 8.83. The median is 8.5, the mode is 7, and the range is 12 – port, you should present these statistics for both conditions in a clear comparison table.
例如，如果你的记忆测试得分为 7、9、8、10、12、7，平均数将是 (7+9+8+10+12+7)/6 = 53/6 ≈ 8.83。中位数为 8.5，众数为 7，极差为 12 – 7 = 5。在你的报告中，你应该将这些统计量清晰地呈现在比较表格中，对比两种条件。
9. Presenting and Interpreting Results | 呈现与解释结果
WJEC requires you to display results in appropriate graphical forms, most commonly bar charts or tables. A bar chart can be used to compare the mean performance of two conditions visually. When drawing a bar chart, label both axes clearly, give the chart a title, and include error bars if instructed, although at GCSE level a simple bar chart with the DV on the y‑axis and the IV conditions on the x‑axis is sufficient.
WJEC 要求你以适当的图形形式展示结果，最常见的是条形图或表格。条形图可以用来直观地比较两种条件的平均表现。绘制条形图时，要清晰地标注两个坐标轴，给图表加上标题，并在要求时包含误差线，但在 GCSE 水平，一个简单的以纵轴表示因变量、横轴表示自变量条件的条形图就足够了。
Interpretation involves linking your descriptive statistics back to your hypotheses. If the mean for the experimental condition is noticeably higher than the control condition, you can tentatively conclude that the IV had an effect. However, you must be cautious — a difference in means does not prove a hypothesis unless supported by inferential statistical analysis, though for your practical you may just discuss the descriptive patterns and state whether the alternative or null hypothesis is supported.
解释包括将你的描述统计与假设联系起来。如果实验条件的平均数明显高于控制条件，你可以初步推断自变量产生了效应。然而，你必须保持谨慎——平均数上的差异并不能证明假设，除非有推论统计分析的支持，但在你的实践中，你可以仅讨论描述性模式，并陈述是支持备择假设还是零假设。
Never overstate your conclusions. Use phrases like 'The results suggest that...' or 'This pattern indicates...' rather than 'This proves that...'.
切勿夸大你的结论。使用诸如“结果表明……”或“这一模式显示……”之类的表述，而不是“这证明了……”。
10. Writing the Practical Report | 撰写实践报告
The practical report is the final outcome of your investigation and must follow a recognised structure. WJEC commonly expects the following sections: Title, Introduction, Method, Results, and Discussion (including a conclusion and evaluation). Writing clearly and concisely is more important than length.
实践报告是你调查的最终成果，必须遵循公认的结构。WJEC 通常期望以下部分：标题、引言、方法、结果和讨论（包括结论与评估）。清晰简洁的写作比篇幅更重要。
- Title: a concise statement that captures the IV and DV, e.g. 'An investigation into the effect of time of day on reaction speed'.
- Introduction: outline the background theory and aim of your study, and state your experimental and null hypotheses.
- Method: split into design, participants, apparatus/materials, and procedure. Be detailed enough that another researcher could replicate your study exactly.
- Results: present descriptive statistics and a graph, and write a short summary of what the numbers show.
- Discussion: interpret your findings, link back to your hypotheses and background research, point out limitations, and suggest improvements for future studies.
- 标题：一个简洁的陈述，涵盖自变量和因变量，例如“关于一天中不同时间对反应速度影响的调查”。
- 引言：概述研究的背景理论和目的，并陈述你的实验假设和零假设。
- 方法：细分为设计、参与者、仪器/材料以及程序。要足够详细，以便其他研究者能够精确地重复你的研究。
- 结果：呈现描述统计和图表，并撰写一段关于数字所显示内容的简短总结。
- 讨论：解释你的发现，将其与假设和背景研究联系起来，指出局限性，并提出未来研究的改进建议。
11. Evaluating the Investigation | 评估调查
Evaluation is a higher-order skill that distinguishes good reports. You need to discuss the validity and reliability of your study. Internal validity asks whether your procedure genuinely tested what you intended to test; external validity concerns whether your findings can be generalised to real-world settings and other populations.
评估是一项高阶技能，它让好的报告脱颖而出。你需要讨论研究的效度和信度。内部效度询问你的程序是否真正测量了你想要测量的东西；外部效度则关注你的发现能否被推广到现实环境和其他人群。
Reliability refers to the consistency of your results. If you repeated the experiment, would you obtain similar findings? You can improve reliability by standardising procedures and using operationalised variables. Comment on any anomalies in your data, such as an outlier that may have been caused by a participant misunderstanding the instructions.
信度指的是结果的一致性。如果你重复这个实验，你是否会得到相似的结果？你可以通过标准化程序和操作化变量来提高信度。对数据中的任何异常值进行评论，例如由于参与者误解指导语而可能导致的异常值。
Always suggest at least two specific modifications that would address the weaknesses you have identified. For example, if you used an opportunity sample of friends, note that this may have introduced bias, and recommend using stratified sampling from a wider population in future research. This demonstrates critical thinking and ensures you meet the higher mark bands.
始终至少提出两条具体的修改建议，以解决你所找出的不足。例如，如果你使用了朋友组成的机会样本，要指出这可能引入了偏差，并建议在未来的研究中从更广泛的人群中使用分层抽样。这展示了批判性思维，并能确保你达到更高的分数档次。
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