📚 Year 8 OCR Statistics: Vocabulary Terminology Quick Memorisation Guide | Year 8 OCR 统计：词汇术语速记指南
Welcome to your ultimate revision guide for Year 8 OCR Statistics vocabulary. Whether you are preparing for a test or just want to strengthen your foundation, this article will help you memorise key terms efficiently with definitions, examples, and clever mnemonics. Let’s transform tricky jargon into second nature.
欢迎来到 Year 8 OCR 统计词汇终极复习指南。无论你是备考还是巩固基础，这篇文章都将通过定义、示例和巧妙的助记法，帮助你高效记忆关键术语。让我们把难懂的术语变成你的本能。
1. Types of Data | 数据类型
Data is the raw material of statistics. It is broadly split into categorical (qualitative) data and numerical (quantitative) data. Categorical data describes qualities or groups, like ‘favourite colour’ or ‘type of vehicle’. Numerical data consists of numbers and is further divided into discrete and continuous. Discrete data can only take specific, separate values — usually whole numbers, such as ‘number of pets’ or ‘goals scored’. Continuous data can take any value within a range and is obtained by measuring, like ‘height’, ‘mass’, or ‘time’. A useful trick: if you ask “How many?” (counting), it’s discrete. If you ask “How much?” (measuring), it’s continuous.
数据是统计的原材料。它大致分为分类（定性）数据和数值（定量）数据。分类数据描述品质或组别，比如“最喜欢的颜色”或“车辆类型”。数值数据由数字组成，并进一步分为离散型和连续型。离散数据只能取特定的、分离的值——通常是整数，如“宠物数量”或“进球数”。连续数据可以在一个范围内取任意值，通过测量获得，如“身高”、“质量”或“时间”。一个实用技巧：如果你问“多少（个）？”（计数），就是离散型。如果你问“多少（量）？”（测量），就是连续型。
| Data Type | Description | Examples |
| Categorical (Qualitative) | Non-numerical labels or categories | Hair colour, car brand, country |
| Numerical (Quantitative) – Discrete | Counted, distinct values | Shoe size, number of books, siblings |
| Numerical (Quantitative) – Continuous | Measured, any value in an interval | Temperature, length, volume, speed |
2. Mean, Median, Mode, Range | 平均数、中位数、众数、极差
These four measures summarise a data set. Mean is the arithmetic average: add all values and divide by the count. For the numbers 4, 8, 10, the sum is 22 and the mean is 22 ÷ 3 = 7.33 (to 2 d.p.).
这四种度量可以概括一个数据集。平均数是算术平均值：将所有值相加再除以个数。对于数字 4, 8, 10，总和为 22，平均数为 22 ÷ 3 ≈ 7.33（保留两位小数）。
Mean = Σx ÷ n
平均数 = 总和 ÷ 个数
Median is the middle value when data is ordered from smallest to largest. If there is an even number of values, median is the mean of the two middle numbers. Example: in 3, 5, 8, 12, the median is (5+8)/2 = 6.5.
中位数是将数据从小到大排序后中间的值。如果数据个数为偶数，中位数是中间两个数的平均值。例如：在 3, 5, 8, 12 中，中位数为 (5+8)/2 = 6.5。
Mode is the value that appears most frequently. A set can be unimodal, bimodal or have no mode. In the list 2, 4, 4, 6, 7, 7, 7, the mode is 7.
众数是出现最频繁的值。集合可以是单峰的、双峰的或无众数。在列表 2, 4, 4, 6, 7, 7, 7 中，众数为 7。
Range is the difference between the largest and smallest values, measuring spread. For 9, 12, 15, 20, range = 20 – 9 = 11.
极差是最大值与最小值之差，衡量离散程度。对于 9, 12, 15, 20，极差 = 20 – 9 = 11。
Memorisation aid: ‘Mean is Mean with Math, Median is Middle, Mode is Most, Range is Reach (from low to high).’
记忆口诀：平均数 (Mean) 即“均”，中位数 (Median) 取“中”，众数 (Mode) 选“众”，极差 (Range) 看“跨”。
3. Frequency Tables | 频数表
A frequency table organises raw data by listing each unique value alongside how many times it occurs (its frequency). It may also include a tally column to help with counting. Using a frequency table makes it much easier to calculate the mean, mode and median for larger data sets.
频数表通过列出每个唯一值及其出现的次数（即频数）来整理原始数据。它还可以包含一个记数栏来辅助计数。使用频数表可以更轻松地计算大数据集的平均数、众数和中位数。
To find the mean from a frequency table, multiply each value by its frequency, sum those products, and divide by the total frequency. The mode is simply the value with the highest frequency. To find the median, consider the cumulative frequency and locate the middle position.
要从频数表求平均数，用每个值乘以它的频数，把这些乘积相加，再除以总频数。众数就是频数最高的值。要找到中位数，需考虑累积频数并定位到中间位置。
Example: Test scores: 5 (f=3), 6 (f=2), 7 (f=5). Total frequency = 10. Mean = (5×3 + 6×2 + 7×5) ÷ 10 = (15+12+35) ÷ 10 = 6.2. Mode = 7 (highest frequency). Median: order 5,5,5,6,6,7,7,7,7,7; middle two are 6 and 7, median = 6.5.
示例：测试分数：5（频数3），6（频数2），7（频数5）。总频数 = 10。平均值 = (5×3 + 6×2 + 7×5) ÷ 10 = (15+12+35) ÷ 10 = 6.2。众数 = 7（最高频数）。中位数：排序后为 5,5,5,6,6,7,7,7,7,7；中间两个为 6 和 7，中位数 = 6.5。
4. Bar Charts and Pictograms | 条形图与象形图
Bar charts display categorical data with rectangular bars where the length (or height) represents the frequency. Bars must be of equal width and there should be gaps between them to show the categories are separate. Remember to label both axes and give the chart a title.
条形图用矩形条表示分类数据，条的长度（或高度）代表频数。条宽必须相等，且条与条之间要有间隙，以表明类别是独立的。切记给两轴加上标签，并为图表添加标题。
Pictograms (pictographs) use pictures or symbols to represent a certain number of items. A key must be provided, e.g., 1 smiley face = 2 students. Pictograms make data visually engaging but require careful scaling for fractional symbols.
象形图使用图片或符号来表示一定数量的项目。必须提供图例，例如 1 个笑脸 = 2 名学生。象形图使数据生动有趣，但在使用部分符号时需要仔细换算。
5. Pie Charts and Angles | 饼图与角度
A pie chart is a circular graph divided into sectors, where each sector represents a category. The angle of each sector is proportional to the frequency. The total angle in a pie chart is 360 degrees, and the total frequency represents the whole ‘pie’.
饼图是一个被分为若干扇区的圆形图表，每个扇区代表一个类别。每个扇区的角度与频数成比例。饼图的总角度为 360 度，总频数代表整个“饼”。
Sector Angle = (Category Frequency ÷ Total Frequency) × 360°
扇区角度 = (类别频数 ÷ 总频数) × 360°
For example, if 12 out of 60 students prefer drama, the sector angle = (12/60) × 360° = 72°. Always check your angles sum to 360°.
例如，如果 60 名学生中有 12 人喜欢戏剧，扇区角度 = (12/60) × 360° = 72°。务必检查所有角度之和是否为 360°。
6. Probability Scale | 概率尺度
Probability measures how likely an event is to happen. It is expressed as a number between 0 and 1, or as a percentage between 0% and 100%. 0 means impossible, 1 means certain. In OCR Year 8, you often see probability as a fraction, decimal or percentage.
概率衡量一个事件发生的可能性。它用 0 到 1 之间的数字表示，或用 0% 至 100% 的百分数表示。0 表示不可能，1 表示必然。在 OCR Year 8 中，概率常以分数、小数或百分数出现。
P(Event) = Number of favourable outcomes / Total number of equally likely outcomes
概率 = 有利结果的数量 / 所有等可能结果的总数
Key vocabulary: ‘Event’ is the outcome or set of outcomes you are interested in. ‘Sample space’ is the set of all possible outcomes. Probability can also be described with words: certain, likely, even chance, unlikely, impossible.
关键术语：“事件”是你感兴趣的某个或某组结果。“样本空间”是所有可能结果的集合。概率也可以用词语描述：必然、很可能、均等机会、不太可能、不可能。
7. Outcomes and Sample Space | 结果与样本空间
When you roll a fair six-sided die, the sample space is {1, 2, 3, 4, 5, 6}. The event ‘rolling an even number’ includes outcomes 2, 4, 6. Listing outcomes systematically helps ensure none are missed. You can use a table, a tree diagram, or a list.
当你掷一个公平的六面骰子时，样本空间是 {1, 2, 3, 4, 5, 6}。事件“掷出偶数”包括结果 2, 4, 6。系统性地列出结果有助于避免遗漏。你可以使用表格、树状图或列表。
For two-stage events, like flipping a coin and rolling a die, a sample space diagram (or grid) organises all combinations. The probability of ‘a head and an even number’ can then be found by counting favourable cells divided by total cells.
对于两阶段事件，如抛硬币并掷骰子，样本空间图表（或网格）可整理出所有组合。则“正面且偶数”的概率可通过计算有利格子数除以总格子数得到。
8. Grouped Data and Modal Class | 分组数据与众数类
Sometimes data is presented in groups (class intervals) rather than individual values, especially for continuous data like heights. The class containing the median or mode is called the median class or modal class. In grouped data, the modal class is the class interval with the highest frequency.
有时数据以组（组距）的形式呈现，而非单个值，尤其是对于身高这类连续数据。包含中位数或众数的组被称为中位数组或众数类。在分组数据中，众数类是频数最高的组距。
For example, if a table shows: 0 < h <= 10 cm (f=5), 10 < h <= 20 cm (f=12), 20 < h <= 30 cm (f=7), the modal class is 10 < h <= 20 cm. You cannot find an exact mode, only the class interval where the mode lies.
例如，若表格显示：0 < h ≤ 10 cm（频数=5），10 < h ≤ 20 cm（频数=12），20 < h ≤ 30 cm（频数=7），众数类为 10 < h ≤ 20 cm。你无法找到精确的众数，只能找出众数所在的组距。
Note that ‘<= h <=' style notation is used; sometimes > or < symbols appear. Be careful with boundaries.
注意使用“≤ h ≤”这类符号；有时会出现大于或小于号。务必留意边界。
9. Statistical Enquiry Cycle (PPDAC) | 统计探究循环
OCR often refers to the PPDAC cycle: Problem, Plan, Data, Analysis, Conclusion. This is a framework for any statistical investigation. Problem: define a clear question. Plan: decide what data to collect and how. Data: collect and organise information. Analysis: calculate statistics and draw graphs. Conclusion: interpret results and answer the question.
OCR 常会提到 PPDAC 循环：问题、计划、数据、分析、结论。这是任何统计调查的框架。问题：明确一个问题。计划：决定收集什么数据及如何收集。数据：收集并整理信息。分析：计算统计量并绘制图表。结论：解读结果并回答问题。
Memorising PPDAC can be done with a phrase like ‘Please Prepare Data And Conclude’ or ‘Penguins Playfully Dance Around Clouds’. Use whatever works for you.
记忆 PPDAC 可以用短语“请准备数据并得出结论”（Please Prepare Data And Conclude）或“企鹅欢快地绕着云朵跳舞”（Penguins Playfully Dance Around Clouds）。选择适合你的方法。
10. Top Memorisation Tips | 记忆妙招
Use acronyms and acrostics: ‘Mr. MMM Range’ for Mean, Median, Mode, Range. For categorical vs numerical, think ‘Cat-Q’ for categorical, ‘Num-Q’ for quantitative. Create flashcards with the term on one side and definition plus example on the other. Practice drawing a ‘vocabulary map’ linking related words.
使用缩略词和藏头诗：MMM 极差先生（Mr. MMM Range）代表平均数、中位数、众数、极差。分类与数值，可联想“Cat-Q”（定性猫）与“Num-Q”（定量数）。制作抽认卡，一面写术语，另一面写定义和示例。练习绘制“词汇图”，将相关词语连接起来。
Teach a friend: explaining a concept aloud forces you to understand it deeply. When revising, always write down the term, say its meaning, and sketch an example. Repetition and active recall are your best friends for long-term retention.
教朋友：向他人解释一个概念会迫使你深入理解。复习时，要随时写下术语、说出含义并画出示例。重复和主动回忆是保持长期记忆的最佳伙伴。
Published by TutorHao | Statistics Revision Series | aleveler.com
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