Year 7 OCR Statistics: Vocabulary and Terminology Quick Memorisation Guide | 七年级OCR统计：词汇术语速记指南

📚 Year 7 OCR Statistics: Vocabulary and Terminology Quick Memorisation Guide | 七年级OCR统计：词汇术语速记指南

Welcome to your quick guide for mastering key statistical terms in Year 7 OCR Statistics. Memorising vocabulary is the first step to understanding data, and this article breaks everything down into bite-sized chunks with memory aids in both English and Chinese.

欢迎阅读七年级OCR统计关键术语速记指南。熟记术语是理解数据的第一步，这篇文章将把每个概念拆解成小块，并配有中英双语记忆辅助，让学习变得轻松高效。

1. Why Terminology Matters | 术语为何重要

Statistical words act as a shared language. If you call a ‘bar chart’ a ‘histogram’ by mistake, you lose marks because they convey different information. Using the right term shows the examiner that you truly understand the data.

统计词汇是一种共同语言。如果你把“柱形图”误称为“直方图”，就会失分，因为它们传递的信息不同。使用正确的术语能让考官看到你真正理解了数据。

Many exam questions are designed to test whether you can distinguish between similar-sounding ideas such as ‘mean’ and ‘median’ or ‘discrete’ and ‘continuous’. Learning the precise definitions early helps you avoid confusion later.

许多考题旨在考查你是否能区分听起来相似的概念，比如“平均数”和“中位数”或“离散”和“连续”。尽早掌握准确定义，可以让你在后续学习中避免混淆。

2. Data Types: Qualitative and Quantitative | 数据类型：定性与定量

Qualitative data (also called categorical data) describes qualities or categories that cannot be measured with numbers. Examples include favourite colour, types of pet, or hair colour. You can observe it and put it into groups, but you cannot find a meaningful average of ‘brown hair’ and ‘blonde hair’.

定性数据（又称分类数据）描述的是无法用数字衡量的属性或类别。例如最喜欢的颜色、宠物种类或发色。你可以观察并将其分组，但无法为“棕发”和“金发”计算出有意义的平均数。

Quantitative data is numerical information that you can count or measure. This includes things like height, temperature, test scores, and the number of students in a class. Quantitative data allows you to perform calculations and find averages.

定量数据是你可以计数或测量的数值信息，包括身高、温度、考试成绩和班级学生人数等。定量数据可以进行计算并求出平均值。

Quick memory cue: ‘Qualitative’ sounds like ‘quality’ (描述性质) and ‘Quantitative’ contains ‘quantity’ (数量).

快速记忆提示：’Qualitative’ 与 “quality（性质）” 发音相似，而 ‘Quantitative’ 里包含 “quantity（数量）”。

3. Discrete vs Continuous Data | 离散数据与连续数据

Discrete data can only take specific, separate values – often whole numbers. You get it by counting. For instance, the number of books in a bag (5, 6, 7 but never 5.3) or shoe sizes (whole and half sizes) are discrete. Think ‘Discrete starts with D = counting dots’.

离散数据只能取特定的、分隔的值——通常是整数。它是通过计数获得的。例如，书包里的书本数量（5本、6本、7本，不会出现5.3本）或鞋码（整码和半码）都是离散的。记住：“离散”的“离”可以联想为“一粒一粒分开的”。

Continuous data can take any value within a range. You obtain it by measuring. Height (172.4 cm), time taken to run 100 m (13.25 s), and the mass of an apple are continuous because there are infinite possible values between two points.

连续数据可以在一个范围内取任意值，是通过测量获得的。身高（172.4厘米）、百米跑用时（13.25秒）和苹果的质量都属于连续数据，因为在两个点之间存在无数个可能的值。

Pupils often mix these up. A helpful test: ask yourself ‘Can I get a more precise value if I use a better instrument?’ If yes, it is probably continuous. If the value jumps from one whole number to the next, it is discrete.

学生经常混淆这两者。一个有用的检验方法是自问：“如果我使用更精密的工具，能获得更精确的值吗？” 如果可以，那么它很可能是连续数据；如果数值从一个整数直接跳到下一个整数，那它就是离散数据。

4. Primary and Secondary Data | 初级和次级数据

Primary data is information you collect yourself, first-hand, for a specific purpose. Running a survey in your class, measuring the length of leaves, or timing how long a candle burns are all examples of primary data collection.

初级数据是你自己为特定目的直接收集的第一手信息。在班级里进行问卷调查、测量叶子的长度或记录蜡烛燃烧的时间，都是收集初级数据的例子。

Secondary data is data that someone else has already collected, and you are using it for your own investigation. This could be weather records from a website, population statistics published by the government, or results from last year’s sports day.

次级数据是别人已经收集好的数据，你将其用于自己的研究。比如网站上的天气记录、政府发布的人口统计数据，或去年运动会的结果，都属于次级数据。

Memory trick: ‘Primary starts with P = Personal, you do it yourself. Secondary starts with S = Someone else’s work.’ This helps you decide which type of data you are working with.

记忆技巧：“初级”的英文 Primary 以 P 开头，对应“亲自（Personal）收集”；“次级”的 Secondary 以 S 开头，代表“别人的（Someone else’s）成果”。

5. Populations and Samples | 总体与样本

The population is the entire group of individuals or items that you are interested in. If you want to know the favourite crisp flavour of all Year 7 students in your school, the population is every Year 7 student in the school.

总体是你感兴趣的全部个体或事物组成的完整集合。如果你想知道全校七年级学生最喜欢的薯片口味，那么总体就是学校里的每一位七年级学生。

A sample is a smaller group selected from the population. It is often impossible or too time-consuming to survey every member of a population, so we take a representative sample and use its results to estimate what the whole population might look like.

样本是从总体中选出的一个较小群体。由于调查总体中的每一位成员通常不可能或过于耗时，我们会选取一个具有代表性的样本，用其结果来推测总体的情况。

A good sample should be unbiased and large enough to reflect the diversity of the population. Asking only your friends would give a biased sample; picking names randomly from the register is fairer.

一个好的样本应该是无偏的，并且足够大，以反映总体的多样性。只询问你的朋友会产生有偏样本；而从名册中随机抽取姓名则更加公平。

6. Mean, Median, Mode: The Three M’s | 平均数、中位数与众数：三个M

These three terms are all measures of central tendency, telling you where the centre of your data lies. Remember them as M–M–M.

这三个术语都是集中趋势的度量，告诉你数据的中心在哪里。用 M–M–M 来记住它们。

The mean is what most people call the ‘average’. It is found by adding up all the values and dividing by the number of data items.

平均数就是大多数人所说的“平均值”。计算方法是把所有数值加起来，再除以数据的个数。

Mean = (Sum of all data values) ÷ (Number of values)

平均数 = (所有数值之和) ÷ (数值的个数)

The median is the middle value when the data set is ordered from smallest to largest. If there are two middle numbers, the median is their mean.

中位数是将数据集从小到大排列后，位于最中间的那个值。如果有两个中间数，则中位数是这两个数的平均数。

The mode (or modal value) is the value that appears most often. A set of data can have one mode, more than one mode (bimodal), or no mode at all if every value occurs equally often.

众数是出现次数最多的数值。一组数据可以有一个众数、多个众数（双众数），或者完全没有众数（如果每个值出现次数相同）。

A handy saying: ‘Mode = Most, Median = Middle, Mean = you do the most Maths.’ Also, be aware that an outlier (an extreme value) can drag the mean up or down, but the median stays relatively stable.

一个顺口溜：众数看最多，中位数站中间，平均数算到头大。另外要注意，异常值（极端值）会拉高或拉低平均数，但中位数相对稳定。

7. Range: The Simplest Measure of Spread | 极差：最简单的离散度量

The range tells you how spread out your data is. It is found by subtracting the smallest value (minimum) from the largest value (maximum).

极差表示数据的散布程度。计算方法是用最大值减去最小值。

Range = Maximum − Minimum

极差 = 最大值 − 最小值

A small range means the data points are close together, while a large range shows greater variability. For example, if the heights in Class A range from 148 cm to 152 cm (range = 4 cm) and in Class B from 140 cm to 160 cm (range = 20 cm), then Class B has much more variation in height.

极差小表示数据点比较集中，极差大说明变异性更大。例如，A班身高范围从148厘米到152厘米（极差=4厘米），B班从140厘米到160厘米（极差=20厘米），那么B班的身高差异要大得多。

Students often forget to subtract and simply quote the two numbers. Remember: the range is always a single number, not a pair of numbers like ‘140 cm to 160 cm’.

学生常犯的错误是忘记相减，直接给出两个数字。请记住：极差始终是一个单一的数，而不是像“140厘米到160厘米”这样的一对数字。

8. Frequency, Tally Marks and Tables | 频数、计数符与频数表

Frequency simply means the number of times something occurs. When you record how many students chose ‘blue’ as their favourite colour, that count is the frequency of ‘blue’.

频数就是指某个事件发生的次数。当你记录有多少学生选择“蓝色”作为最喜欢的颜色时，那个记录的数字就是“蓝色”的频数。

Tally marks are a quick way to count frequencies. The standard method is to make vertical strokes in groups of five: four vertical lines and a diagonal line through them (卌). This makes it easy to count up in 5s later.

计数符是快速记录频数的方法。标准做法是每五个为一组：先画四条竖线，第五个用一条斜线穿过它们（卌）。这样一来，按5个一组计数就非常方便。

Once you have your tally, you can organise the data into a frequency table. A frequency table lists each category or data value, the tally, and the frequency. It instantly shows you which values are most and least common, and helps you find the mode.

完成计数后，你可以将数据整理成频数表。频数表会列出每个类别或数据值、计数符和频数。它能让你一眼看出哪些值最常见和最不常见，并有助于找出众数。

9. Charts and Graphs at a Glance | 常见图表一览

Different statistical diagrams serve different purposes. Knowing which one to use and how to describe it is a key Year 7 skill. The table below summarises four core charts you will encounter.

不同的统计图表有不同的用途。知道选用哪种图表以及如何描述它是七年级的重要技能。下表总结了你会遇到的四种核心图表。

Chart	Key Features	图表	关键特征
Bar Chart	Bars with equal gaps between them; used for categorical or discrete data. The height shows frequency.	柱形图	条与条之间有等距间隔；用于分类数据或离散数据。柱高表示频数。
Pictogram	Uses pictures or symbols to represent data. Each symbol stands for a certain number of items. The key is essential.	象形图	用图片或符号表示数据。每个符号代表一定数量的项目，图例是必不可少的。
Pie Chart	A circle divided into sectors. It shows proportions of a whole. Each sector angle is proportional to its frequency.	饼图	将圆分割成扇形，显示各部分占整体的比例。每个扇形的圆心角与其频数成正比。
Line Graph	Points connected by straight lines. Best for showing trends over time (time series). Often uses continuous data.	折线图	用点及连接它们的线段显示数据。最适合展示随时间变化的趋势（时间序列），常用于连续数据。

Common errors include drawing bars that touch in a bar chart (they should be separate) or using a line graph for categorical data. Always check that your graph has a clear title and labelled axes.

常见的错误包括：画柱形图时让条与条挨在一起（它们应该分开）、对分类数据使用折线图。始终要确保图表有清晰的标题和标注过的坐标轴。

10. Memory Tricks and Common Pitfalls | 记忆技巧与常见陷阱

Here is a compact set of memory aids to lock in the key vocabulary. Rehearse them before a test.

这里有一套紧凑的记忆辅助工具，助你牢牢掌握关键词汇。考试前多加练习。

‘Qualitative = Quality, Quantitative = Quantity’ – 定性看性质，定量看数量。
‘Discrete = Counted (dots on a die), Continuous = Measured (scale)’ – 离散是数出来的（如骰子点数），连续是量出来的（如秤上的刻度）。
‘Primary = Personal, Secondary = Someone else’s’ – 初级数据自己来，次级数据别人给。
‘Population = Everyone, Sample = a Slice’ – 总体是全部，样本是一部分。
‘Mean = Sum ÷ n, Median = Middle, Mode = Most’ – 平均数用除和加，中位数找正中间，众数就是最常见。
‘Range = Max − Min’ – 极差记减法，最大减最小。

Pitfalls to watch for: confusing the terms ‘mean’ and ‘median’ when explaining an average; forgetting to put data in order before finding the median; including an outlier when it would be fairer to use the median; and not reading the key on a pictogram, which can lead to huge mistakes in frequency.

需要留意的陷阱有：解释平均值时混淆“平均数”和“中位数”；找中位数前忘记排序；在存在异常值时仍然使用平均数（此时中位数可能更合理）；以及看象形图时漏掉图例，导致频数出现重大错误。

Finally, always ask yourself: ‘What type of data do I have, and what is the best way to summarise it?’ This simple question will guide you toward the correct vocabulary and the most suitable statistical tool.

最后，记得问自己：“我手头是哪种类型的数据？总结它的最佳方式是什么？”这个简单的问题会引导你使用正确的术语和最适合的统计工具。

Published by TutorHao | Statistics Revision Series | aleveler.com

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Year 7 OCR Statistics: Vocabulary and Terminology Quick Memorisation Guide | 七年级OCR统计：词汇术语速记指南