📚 Year 10 CCEA Statistics: A Quick Guide to Key Terms | Year 10 CCEA 统计：关键术语速记指南
Mastering statistical vocabulary is essential for success in Year 10 CCEA Statistics. This guide presents key terms alongside memory aids to help you recall definitions and apply them correctly in exams.
掌握统计词汇对于在 Year 10 CCEA 统计考试中取得成功至关重要。本指南提供关键术语及记忆技巧，帮助你回忆定义并在考试中正确应用。
1. Types of Data | 数据类型
The two main types of data are qualitative and quantitative. Qualitative data (categorical) represent characteristics like hair colour or gender. Quantitative data involve numbers and are either discrete or continuous.
数据的主要类型有定性和定量。定性（分类）数据代表特征，如头发颜色或性别。定量数据涉及数字，分为离散或连续。
Discrete data are countable—think ‘discrete’ like separate steps. Examples: number of goals, shoe size. Continuous data can take any value in an interval—think ‘continuous’ like a smooth line. Examples: height, time.
离散数据是可数的——想象成独立的台阶。例如：进球数、鞋码。连续数据可以在区间内取任何值——想象成平滑的线。例如：身高、时间。
Memory aid: Discrete = ‘distinct, countable’; Continuous = ‘connected, measurable’.
记忆口诀：离散 = 可分辨、可数；连续 = 相连、可测。
2. Measures of Central Tendency | 集中趋势度量
The mean is the arithmetic average, calculated by summing all values and dividing by the number of values: Mean = Σx ÷ n, where Σx is the sum and n is the number of values.
平均数是算术平均值，通过将所有值相加然后除以值的个数计算得出：平均数 = Σx ÷ n，其中 Σx 是总和，n 是数值个数。
The median is the middle value when data are ordered. If there is an even number of values, the median is the average of the two middle numbers.
中位数是将数据排序后位于中间的值。如果数据个数是偶数，中位数是中间两个数的平均值。
The mode is the value that appears most often. A set may have one mode, more than one mode, or no mode at all.
众数是数据集中出现次数最多的数值。一个数据集可能有一个众数、多个众数或无众数。
Memory hooks: Mean = ‘mean’ teacher averages your grades; Median = ‘middle’ like median strip on a motorway; Mode = ‘most’ starts with M.
记忆挂钩：平均数 (mean) 想想老师平均你的分数；中位数 (median) 像高速公路的中央分隔带 (median strip)；众数 (mode) 与“最多” (most) 都以 M 开头。
3. Measures of Spread | 离散度量
The range is the difference between the largest and smallest values: Range = max – min. It gives a simple measure of spread.
极差（全距）是最大值与最小值之差：极差 = 最大值 – 最小值，提供简单的离散度量。
Quartiles divide an ordered data set into four equal parts. The lower quartile (Q1) is the median of the lower half, the upper quartile (Q3) is the median of the upper half.
四分位数将有序数据集等分为四部分。下四分位数 (Q1) 是下半部分的中位数，上四分位数 (Q3) 是上半部分的中位数。
The interquartile range (IQR) = Q3 − Q1. It measures the spread of the middle 50% and is less affected by outliers.
四分位距 (IQR) = Q3 − Q1。它衡量中间 50% 数据的离散程度，受异常值影响较小。
Memory: ‘Quart’ suggests 4; imagine cutting a cake into 4 equal slices. IQR is the ‘middle spread’.
记忆：quart 有“四”的意思；想象把蛋糕切成四等份。IQR 是“中间部分的离散度”。
4. Box Plots and Cumulative Frequency | 箱线图与累积频率
A box plot (box-and-whisker plot) visually represents the five-number summary: minimum, Q1, median, Q3, and maximum.
箱线图（盒须图）用图形展示五数概括：最小值、Q1、中位数、Q3 和最大值。
The box spans from Q1 to Q3 with a line at the median. Whiskers extend to the minimum and maximum values within 1.5 × IQR boundaries, marking potential outliers.
箱体从 Q1 延伸至 Q3，内部中位线；须线延伸至最小值和最大值，超出 1.5 倍 IQR 边界的数据点视为可能的异常值。
Cumulative frequency is the running total of frequencies. A cumulative frequency graph shows the number of observations less than or equal to a given value.
累积频率是频率的累加总和。累积频率图显示小于等于某个给定值的观测数量。
Memory: ‘Box’ contains the middle half, ‘whiskers’ reach out to extremes. Cumulative = ‘accumulating total’.
记忆：“箱”包含中间一半，“须”伸向两极。累积 = 累加总合。
5. Histograms and Frequency Density | 直方图与频率密度
A histogram is used for continuous data grouped into classes. The area of each bar is proportional to the frequency. The height is the frequency density, calculated as frequency density = frequency ÷ class width.
直方图用于连续数据分组。每个柱形面积与频率成正比。柱高是频率密度，计算为 频率密度 = 频率 ÷ 组距。
Frequency density ensures that wider intervals are represented fairly. In a histogram, frequency = frequency density × class width.
频率密度确保较
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