📚 AQA Year 9 Psychology: Experimental & Practical Assessment Key Points | AQA 9年级心理学：实验与实践考核要点
In Year 9 AQA Psychology, you will start learning how to design, conduct, and evaluate simple experiments. Your practical assessments will test your ability to handle variables, follow ethical guidelines, and analyse data. This guide summarises the key points you need to master for your experimental and practical assessments.
在九年级AQA心理学中，你将开始学习如何设计、实施和评估简单的实验。实践考核会测试你处理变量、遵循伦理准则和分析数据的能力。本指南总结了你为实验和实践评估需要掌握的关键要点。
1. Understanding Psychological Experiments | 理解心理学实验
An experiment is a research method where the researcher manipulates one variable (the independent variable, IV) to measure its effect on another variable (the dependent variable, DV), while keeping all other conditions constant.
实验是一种研究方法，研究者操纵一个变量（自变量，IV）来测量它对另一个变量（因变量，DV）的影响，同时保持所有其他条件不变。
This method allows psychologists to establish cause-and-effect relationships between variables, making experiments the most powerful tool for testing hypotheses.
这种方法让心理学家能够确定变量之间的因果关系，使实验成为检验假设最有力的工具。
2. Independent and Dependent Variables | 自变量与因变量
The independent variable (IV) is the factor you change, manipulate, or compare in an experiment. For example, the amount of sleep (4 hours vs. 8 hours).
自变量（IV）是你在实验中改变、操纵或比较的因素。例如，睡眠时间（4小时与8小时）。
The dependent variable (DV) is the outcome you measure. For example, reaction time on a memory test. The DV is expected to change because of the IV.
因变量（DV）是你测量的结果。例如，记忆测试中的反应时间。DV的变化被认为是由IV引起的。
Always operationalise your variables: state exactly how the IV is manipulated and how the DV is measured. For instance, 'IV: 4 hours vs. 8 hours of sleep; DV: number of words recalled from a list of 20.'
一定要将变量操作化：准确说明如何操纵自变量以及如何测量因变量。例如，“IV：4小时与8小时睡眠；DV：从20个单词列表中正确回忆的数量”。
3. Formulating Hypotheses | 提出假设
A hypothesis is a clear, testable prediction about the relationship between the IV and DV. In GCSE Psychology, you must write both an alternative hypothesis (H1) and a null hypothesis (H0).
假设是对自变量和因变量之间关系的清晰、可检验的预测。在GCSE心理学中，你需要写出备择假设（H1）和虚无假设（H0）。
The alternative hypothesis predicts a significant effect or difference. Example: 'There will be a significant difference in the number of words recalled between participants who sleep 4 hours and those who sleep 8 hours.'
备择假设预测存在显著效应或差异。示例：“睡眠4小时和8小时的被试在单词回忆数量上会有显著差异。”
The null hypothesis states that any observed effect is due to chance. Example: 'There will be no significant difference in the number of words recalled between the two groups.'
虚无假设声明任何观察到的效应都是由偶然因素造成的。示例：“两组被试在单词回忆数量上没有显著差异。”
4. Types of Experimental Design | 实验设计类型
Choosing the right experimental design is crucial for controlling participant variables and order effects. The three main designs are outlined below.
选择正确的实验设计对于控制被试变量和顺序效应至关重要。下面是三种主要设计的概要。
| Design (English) | 设计（中文） | Key Features / 主要特征 | Strengths / 优点 | Weaknesses / 缺点 |
|---|---|---|---|---|
| Independent Groups | 独立组设计 | Different participants in each condition. 每个条件下不同的被试。 | No order effects. 无顺序效应。 | Participant variables (individual differences) may affect results. 被试变量（个体差异）可能影响结果。 |
| Repeated Measures | 重复测量设计 | Same participants take part in all conditions. 相同的被试参加所有条件。 | Controls participant variables. 控制被试变量。 | Order effects (practice, fatigue) may occur. 可能出现顺序效应（练习、疲劳）。 |
| Matched Pairs | 配对组设计 | Participants are matched on a key variable, then each pair is split between conditions. 被试在关键变量上配对，每对分配到不同条件。 | Reduces participant variables and no order effects. 减少被试变量且无顺序效应。 | Time-consuming and difficult to match perfectly. 耗时且难以完美匹配。 |
When selecting a design, consider what is practical for your sample size and how you can best minimise confounding variables.
在选择设计时，要考虑样本量的实际情况，以及如何最大限度地减少混淆变量。
5. Controlling Confounding Variables | 控制混淆变量
Extraneous variables are any variables, other than the IV, that could influence the DV if not controlled. When an extraneous variable systematically changes with the IV, it becomes a confounding variable and ruins the internal validity.
无关变量是除自变量外，如果不加控制就可能影响因变量的任何变量。当无关变量随自变量系统变化时，它就成为混淆变量，破坏了内部效度。
Use standardised procedures: keep instructions, environment, timing, and materials exactly the same for all participants.
使用标准化程序：对所有被试保持指导语、环境、时间安排和材料完全一致。
Random allocation: in independent groups designs, randomly assign participants to conditions using a random number generator or drawing names from a hat.
随机分配：在独立组设计中，使用随机数生成器或抽签等方法将被试随机分配到各条件中。
Counterbalancing: in repeated measures designs, vary the order in which participants complete the conditions (e.g., half do condition A first, half do condition B first) to cancel out order effects.
平衡法：在重复测量设计中，变化被试完成条件的顺序（例如一半先做条件A，一半先做条件B），以消除顺序效应。
6. Ethical Considerations | 伦理考量
The British Psychological Society (BPS) sets ethical guidelines that all researchers must follow. The key principles are: informed consent, avoidance of deception (unless necessary and justified), the right to withdraw at any time, confidentiality, protection from physical and psychological harm, and debriefing.
英国心理学会（BPS）制定了所有研究者必须遵守的伦理准则。主要原则包括：知情同意、避免欺骗（除非必要且合理）、随时退出的权利、保密、避免身心伤害以及事后解释。
In Year 9 practical work, you must obtain written consent from participants (and from parents or guardians if participants are under 16). Explain the procedure clearly and remind them they can stop at any moment without giving a reason.
在九年级实践工作中，你必须获得被试（若未满16岁还需家长或监护人）的书面同意。清楚解释程序，并提醒他们可以随时停止，无须给出理由。
During the experiment, ensure no harm comes to participants. Afterwards, hold a debriefing session where you explain the purpose of the study, answer questions, and provide support if needed.
在实验过程中，确保被试不受伤害。实验结束后，进行事后解释，说明研究目的，回答问题，并在需要时提供支持。
7. Sampling Methods | 抽样方法
Sampling is how you select participants from the target population. Three common methods are evaluated below.
抽样是你从目标群体中选择被试的方式。下面是三种常见方法的评估。
Opportunity sampling: using people who are readily available and willing (e.g., friends or classmates). It is quick and convenient, but may produce a biased sample that does not represent the wider population.
机会抽样：使用现成且愿意参加的人（如朋友或同班同学）。快速便捷，但可能产生有偏差的样本，不能代表更广泛的群体。
Random sampling: every member of the population has an equal chance of being chosen (e.g., using a random number generator or drawing names). It reduces sampling bias but is often difficult to achieve in school settings.
随机抽样：群体中的每个成员都有同等被选中的机会（如使用随机数生成器或抽签）。减少抽样偏差，但在学校环境中通常难以实现。
Volunteer sampling: participants self-select by responding to an advert or invitation. This can lead to volunteer bias because those who volunteer may differ in motivation or personality from the general population.
志愿者抽样：被试通过回应广告或邀请自主选择参加。这可能导致志愿者偏差，因为志愿者在动机或性格上可能与总体不同。
8. Data Collection Techniques | 数据收集技术
To measure the dependent variable, you must choose an appropriate data collection tool. Common tools include structured observations, questionnaires, and standardised tests.
为了测量因变量，你必须选择合适的资料收集工具。常用的工具包括结构化观察、问卷和标准化测试。
Ensure your tool is reliable (it produces consistent results across multiple trials) and valid (it genuinely measures what you intend to measure). For example, if testing memory, a list of nonsense syllables may be more valid than meaningful words avoid prior knowledge effects.
确保你的工具是可靠的（在多次试验中产生一致结果）和有效的（它真正测量了你想要测量的东西）。例如，测试记忆力时，无意义音节表可能比有意义单词更有效，以避免先前知识效应。
Record raw data accurately in a table as you collect it. This makes analysis more manageable and reduces errors.
在收集资料时，将原始数据准确地记录在表格中。这使得分析更容易管理，并减少错误。
9. Analysing Data | 分析数据
Descriptive statistics help you summarise and display your findings. The main measures are:
描述性统计帮助你总结和展示你的发现。主要度量包括：
Mean (average): calculated by adding all scores and dividing by the number of scores. It is sensitive to extreme values.
平均数：将所有分数相加再除以分数的个数。它对极端值敏感。
Median (middle value): the middle score when data are ordered. It is unaffected by outliers.
中位数：将数据排序后处于中间位置的分数。它不受异常值的影响。
Mode (most frequent): the score that appears most often. It is easy to spot but not very informative.
众数：出现次数最多的分数。容易识别，但信息量不大。
Range: the difference between the highest and lowest scores. It gives a quick measure of spread but can be distorted by a single extreme value.
极差：最高分与最低分之间的差值。它可快速衡量离散度，但可能被单个极端值扭曲。
Present data in bar charts or line graphs, with clear labels on both axes. The IV typically goes on the X-axis, and the DV on the Y-axis.
用条形图或折线图呈现数据，两个坐标轴都应有清晰标签。自变量通常放在X轴，因变量放在Y轴。
10. Evaluating an Experiment | 评估实验
Evaluation is a critical skill in psychology. It involves judging the quality of your research and suggesting ways to improve it.
评估是心理学中的一项关键技能。它涉及判断研究质量并提出改进方法。
Internal validity: are you confident that changes in the DV were truly caused by the IV, not by confounding variables? Check for uncontrolled extraneous variables.
内部效度：你有多大把握是因变量的变化确实由自变量引起，而不是由混淆变量导致？检查是否存在未控制的无关变量。
External validity (generalisability): can the findings be applied to other groups, settings, or time periods? A small, narrow sample may limit generalisability.
外部效度（推广性）：研究结果能否推广到其他群体、环境或时间段？较小或单一的样本可能会限制推广性。
Reliability: if you repeated the experiment under the same conditions, would you obtain similar results? Unreliable measurement tools or inconsistent procedures reduce reliability.
信度：如果在相同条件下重复实验，会得到相似的结果吗？不可靠的测量工具或不一致的程序会降低信度。
In practical assessments, always suggest at least two concrete improvements, such as using a larger and more diverse sample, controlling an unnoticed extraneous variable, or using a more standardised procedure.
在实践评估中，务必提出至少两点具体的改进建议，例如使用更大且更多样化的样本、控制一个先前未注意到的无关变量，或使用更标准化的程序。
11. Practical Assessment Tasks and Report Writing | 实践考核任务与报告撰写
Typical practical tasks require you to design a simple experiment, carry it out safely and ethically, collect data, and write a structured report. The report should follow the standard psychological format: Title, Aim, Hypothesis, Method, Results, Conclusion, and Evaluation.
典型的实践任务要求你设计一个简单实验，安全且合乎伦理地实施它，收集数据，并撰写结构化的报告。报告应遵循标准心理学格式：标题、目的、假设、方法、结果、结论和评估。
In the Method section, describe the design (e.g., independent groups), participants (number
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