📚 Year 7 Cambridge Statistics: Unit Test Mock Paper Walkthrough | Year 7 剑桥统计：单元测试模拟卷解析
This article walks you through a complete Cambridge Year 7 Statistics mock paper, covering typical questions on averages, charts, probability, and data collection. Each solution is explained step by step to help you revise effectively for your unit test.
本文为你逐题解析一份完整的剑桥 Year 7 统计模拟卷，涵盖平均值、图表、概率和数据收集等常见题型。每道题目的解答都配有逐步讲解，帮助你高效复习单元测试。
1. Overview of the Mock Paper | 模拟卷概述
The mock paper contains 10 questions, each testing a key skill from the Cambridge Year 7 Statistics curriculum. You will need to calculate mean, median, mode, and range; read bar charts, pie charts, and line graphs; understand basic probability; draw Venn diagrams; and use sample space diagrams.
这份模拟卷包含 10 道题，每道题考查剑桥 Year 7 统计课程中的一项关键技能。你需要计算平均值、中位数、众数和极差；阅读条形图、饼图和折线图；理解基础概率；绘制维恩图；以及使用样本空间图。
The total marks are 40, and the suggested time is 45 minutes. Let’s go through each question together.
试卷满分为 40 分，建议完成时间为 45 分钟。让我们一起来逐题分析。
2. Question 1: Mean from a Frequency Table | 第1题：频率表求均值
The question gives the number of pets owned by 20 students in a frequency table. You are asked to calculate the mean number of pets.
题目给出 20 名学生拥有宠物数量的频率表。要求计算宠物的平均数。
First, multiply each number of pets by its frequency. Then add all the products. Finally, divide the total by the sum of frequencies.
首先，将每种宠物数量乘以其频数。然后，将所有乘积相加。最后，用总和除以频数的总和。
For example, if 0 pets (f=4), 1 pet (f=8), 2 pets (f=5), 3 pets (f=3), the total sum is 0×4 + 1×8 + 2×5 + 3×3 = 0+8+10+9 = 27. Mean = 27 ÷ 20 = 1.35 pets.
例如，如果有 0 只宠物（f=4），1 只（f=8），2 只（f=5），3 只（f=3），总和为 0×4 + 1×8 + 2×5 + 3×3 = 0+8+10+9 = 27。平均数 = 27 ÷ 20 = 1.35 只宠物。
Always check that the sum of frequencies matches the total number of data points.
记得检查频数总和是否与数据总数一致。
3. Question 2: Interpreting a Bar Chart | 第2题：条形图解读
A bar chart shows the favourite sports of 30 pupils. You need to read frequencies correctly from the vertical axis and compare categories.
图中显示了 30 名学生最喜爱的运动。你需要从纵轴正确读取频数，并对类别进行比较。
Make sure you check the scale on the y-axis – sometimes it goes up in 2s, 5s, or 10s. Subtract to find how many more pupils prefer one sport than another.
一定要检查 y 轴上的刻度——有时每格代表 2、5 或 10。用减法计算喜欢一种运动比另一种多出多少人。
If football has frequency 12 and tennis has 7, then 5 more pupils prefer football. You might also be asked to write a conclusion, like ‘Football is the most popular sport’.
如果足球的频数是 12，网球是 7，那么喜欢足球的多了 5 人。你可能还需要写一条结论，例如“足球是最受欢迎的运动”。
4. Question 3: Median and Mode | 第3题：中位数和众数
A list of scores is given: 8, 3, 5, 9, 5, 7, 10, 5, 6. You must find the mode and the median.
给出一组分数：8, 3, 5, 9, 5, 7, 10, 5, 6。要求找出众数和中位数。
The mode is the value that appears most often. Here, 5 appears three times, so mode = 5.
众数是出现次数最多的值。这里 5 出现了三次，所以众数 = 5。
For the median, first arrange the numbers in order: 3, 5, 5, 5, 6, 7, 8, 9, 10. The middle value of this 9-number list is the 5th value, which is 6. So median = 6.
求中位数时，先将数字按顺序排列：3, 5, 5, 5, 6, 7, 8, 9, 10。这组 9 个数的中间值是第 5 个，即 6。所以中位数 = 6。
If there are an even number of values, you must find the mean of the two middle numbers.
如果数据个数为偶数，必须求中间两个数的平均数。
5. Question 4: Calculating the Range | 第4题：计算极差
The question provides a set of daily temperatures: 12 °C, 15 °C, 9 °C, 18 °C, 14 °C. Find the range.
题目给出了一组每日气温：12 °C, 15 °C, 9 °C, 18 °C, 14 °C。求极差。
Range = highest value – lowest value. Identify the maximum (18) and the minimum (9), then subtract: 18 – 9 = 9 °C.
极差 = 最大值 – 最小值。找出最大值（18）和最小值（9），然后相减：18 – 9 = 9 °C。
The range tells you how spread out the data are. A larger range means more variation.
极差表示数据的分散程度。极差越大，数据的波动范围就越大。
6. Question 5: Pie Chart Angles | 第5题：饼图角度
You are told that in a survey of 40 students’ transport to school, 10 walk, 20 take the bus, and 10 cycle. Calculate the angle for each sector in a pie chart.
在一项关于 40 名学生上学交通方式的调查中，10 人步行，20 人乘公交，10 人骑自行车。请计算饼图中每个扇形的角度。
Total frequency = 40. The angle for one person = 360° ÷ 40 = 9°. Multiply each frequency by 9°.
总频数 = 40。每个人对应的角度 = 360° ÷ 40 = 9°。将每个频数乘以 9°。
- Walk: 10 × 9° = 90°
- Bus: 20 × 9° = 180°
- Cycle: 10 × 9° = 90°
Always check that the three angles sum to 360°: 90+180+90 = 360.
一定要检查三个角度之和是否为 360°：90+180+90 = 360。
7. Question 6: Data Collection Methods | 第6题：数据收集方法
This question asks you to choose the best data collection method for a given situation: survey, observation, experiment, or using a secondary source.
本题要求你为所给情景选择最佳的数据收集方法：问卷、观察、实验或使用二手资料。
For example, to find out the number of cars passing a road, observation is suitable. To collect opinions on a new school lunch menu, a survey with a questionnaire is best.
例如，要了解通过某条路的汽车数量，适合使用观察法。要收集对新学校午餐菜单的意见，最好是使用问卷进行调查。
You must also design a suitable data collection sheet, including tally marks and clear categories. Make sure the categories do not overlap.
你还需要设计一份合适的数据收集表，包括划记标记和清晰的分类。确保类别之间没有重叠。
8. Question 7: Basic Probability | 第7题：基础概率
A bag contains 3 red, 2 blue, and 5 green marbles. Find the probability of picking a red marble, and the probability of picking a marble that is not blue.
一个袋子装有 3 颗红色、2 颗蓝色和 5 颗绿色弹珠。求摸到红色弹珠的概率，以及摸到不是蓝色弹珠的概率。
Total marbles = 3+2+5 = 10. P(red) = 3/10. P(not blue) = (3+5)/10 = 8/10, which simplifies to 4/5.
弹珠总数 = 3+2+5 = 10。P(红色) = 3/10。P(非蓝色) = (3+5)/10 = 8/10，化简为 4/5。
Probability is always written as a fraction, decimal, or percentage between 0 and 1. In this test, fractions should be given in simplest form.
概率总是写成分数、小数或百分比，范围在 0 到 1 之间。本次测试中，分数应化为最简形式。
9. Question 8: Venn Diagrams | 第8题：维恩图
In a class of 30 students, 18 study French, 15 study Spanish, and 8 study both. Draw a Venn diagram and find how many students study neither language.
在一个 30 名学生的班级中，18 人学习法语，15 人学习西班牙语，8 人两门都学。画出维恩图并求出两门语言都不学的学生人数。
Label the two overlapping circles. Place 8 in the intersection. For French only: 18 – 8 = 10. For Spanish only: 15 – 8 = 7. Total inside the circles = 10+8+7 = 25.
给两个重叠的圆圈做好标注。将 8 放在交集处。只学法语的人数：18 – 8 = 10。只学西班牙语的人数：15 – 8 = 7。圆圈内总人数 = 10+8+7 = 25。
Students studying neither = total class – 25 = 30 – 25 = 5. Place this number outside the circles.
两门都不学的学生 = 班级总数 – 25 = 30 – 25 = 5。将这个数字写在圆圈外面。
10. Question 9: Line Graph Trends | 第9题：折线图趋势
A line graph shows the temperature in a town over 7 days. You must describe the trend and identify the day with the highest temperature.
折线图显示了一个小镇 7 天的气温。你需要描述变化趋势，并指出哪天温度最高。
Read the coordinates carefully. Days are on the horizontal axis, temperatures on the vertical axis. Use phrases like ‘increased rapidly’, ‘remained steady’, or ‘decreased slightly’ to describe trends between points.
仔细读取坐标点。横轴表示日期，纵轴表示温度。使用如“迅速上升”、“保持平稳”或“轻微下降”等短语来描述点与点之间的变化趋势。
Overall trend might be ‘the temperature rose from Monday to Friday, then fell at the weekend’. Always give specific values when asked.
整体趋势可能是“气温从周一到周五上升，然后周末下降”。在被要求时应给出具体数值。
11. Question 10: Sample Space Diagrams | 第10题：样本空间图
Two fair six-sided dice are rolled. Draw a sample space diagram to show all possible outcomes, and find the probability that the sum of the two numbers is greater than 9.
掷两枚公平的六面骰子。画出样本空间图以显示所有可能的结果，并求两数之和大于 9 的概率。
Draw a 6 by 6 grid. List the outcomes (1,1), (1,2) … up to (6,6). There are 36 equally likely outcomes.
画一个 6×6 的网格。列出结果 (1,1), (1,2) …… 直到 (6,6)。共有 36 种等可能的结果。
Outcomes with sum > 9: (4,6), (5,5), (5,6), (6,4), (6,5), (6,6). There are 6 such outcomes. So probability = 6/36 = 1/6.
和大于 9 的结果有：(4,6), (5,5), (5,6), (6,4), (6,5), (6,6)。共 6 种。因此概率 = 6/36 = 1/6。
Always simplify your fraction and double-count systematically to avoid missing any pairs.
始终化简分数，并系统地列举以免遗漏任何组合。
Published by TutorHao | Statistics Revision Series | aleveler.com
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