Question 1 — Elements, Variables, and Observations
In a study about student performance, “students” are the ______, “GPA” is a ______, and “each student’s GPA record” is a(n) ______.
📖 点击查看答案
Elements; Variable; Observation 元素；变量；观测值📝 点击查看解析
统计学中，元素是研究对象（学生），变量是特征（GPA），观测值是每个元素的测量数据（学生的GPA记录）。Question 2 — Nominal Scale
Which of the following is measured on a nominal scale?
A) Temperature in Celsius
B) Student ID number
C) Credit rating (AAA, AA, A, B)
D) Student GPA
📖 点击查看答案
B) Student ID number 学号📝 点击查看解析
名义尺度只用于分类或标记，学号只是身份识别，没有顺序或数量意义。Question 3 — Ordinal Scale
A company evaluates customer satisfaction as “Very satisfied, Satisfied, Neutral, Dissatisfied.” Which measurement scale is used?
📖 点击查看答案
Ordinal scale (顺序尺度)📝 点击查看解析
顺序尺度强调排序意义，尽管等级间差距未必相等。Question 4 — Interval Scale
A student scores 600 on TOEFL while another scores 550. Which scale is used and why?
📖 点击查看答案
Interval scale (区间尺度)📝 点击查看解析
区间尺度有固定间隔，600 与 550 相差 50 分，但不存在绝对零点。Question 5 — Ratio Scale
If Kevin has 80kg weight and Melissa has 40kg weight, what scale is applied?
📖 点击查看答案
Ratio scale (比率尺度)📝 点击查看解析
比率尺度有绝对零点，可以进行比率比较。Kevin 的体重是 Melissa 的两倍。Question 6 — Categorical vs Quantitative
Gender of a person is ______ data, while their height is ______ data.
📖 点击查看答案
Categorical; Quantitative 类别型；数量型📝 点击查看解析
性别是分类信息；身高是可以测量的数值数据。Question 7 — Cross-sectional Data
Which dataset is cross-sectional?
A) Quarterly profits of Apple from 2015 to 2024
B) Survey of 200 people’s income levels in 2024
C) Daily stock price of Tesla in 2023
📖 点击查看答案
B) Survey of 200 people’s income levels in 2024📝 点击查看解析
横截面数据在同一时间点收集；A 和 C 都涉及时间序列。Question 8 — Time Series Data
Tracking U.S. gasoline prices from 2012 to 2018 is an example of ______ data.
📖 点击查看答案
Time series data (时间序列数据)📝 点击查看解析
时间序列数据强调随时间收集的变化趋势。Question 9 — Observational Study
Observing how long customers stay in Walmart without interference is an example of ______ study.
📖 点击查看答案
Observational study (观察性研究)📝 点击查看解析
观察性研究不控制变量，只是记录数据。Question 10 — Experimental Study
In a medical trial, one group receives a vaccine and another receives a placebo. What type of study is this?
📖 点击查看答案
Experimental study (实验性研究)📝 点击查看解析
实验性研究通过控制变量（是否接种疫苗）来观察结果。Question 11 — Data Acquisition Challenges
Name two key challenges of data acquisition.
📖 点击查看答案
Time requirement; Cost of acquisition; Data errors 时间需求；获取成本；数据错误📝 点击查看解析
获取数据可能耗时且昂贵，错误数据可能误导分析。Question 12 — Mean Calculation
If the costs of five parts are 60, 80, $90, what is the mean cost?
📖 点击查看答案
Mean = (50+60+70+80+90)/5 = $70 均值 = $70📝 点击查看解析
均值反映集中趋势，是最常见的数值描述统计。Question 13 — Population vs Sample
Surveying all students in WKU is a ______, while surveying 200 students is a ______.
📖 点击查看答案
Census (普查); Sample survey (抽样调查)📝 点击查看解析
普查是对总体所有元素进行测量，抽样只研究总体的一部分。Question 14 — Descriptive vs Inferential Statistics
Which type of statistics is used to “summarize GPA of surveyed students” and which is used to “predict GPA of all students”?
📖 点击查看答案
Descriptive statistics; Inferential statistics 描述统计；推断统计📝 点击查看解析
描述统计只总结已有数据，推断统计用样本去推测总体。Question 15 — Excel Functions
Which Excel function calculates the maximum value in a dataset?
📖 点击查看答案
=MAX(range)📝 点击查看解析
Excel 提供 MAX、MIN、AVERAGE 等函数来进行基础统计。Question 16 — Analytics Types
Matching:
- Descriptive analysis
- Predictive analysis
- Prescriptive analysis
A) Uses past data to forecast future outcomes
B) Summarizes what happened in the past
C) Recommends best actions
📖 点击查看答案
1 → B; 2 → A; 3 → C📝 点击查看解析
描述性分析总结过去，预测性分析预测未来，规范性分析推荐最佳行动。Question 17 — Big Data
Walmart captures 20–30 million transactions per day. This is an example of ______.
📖 点击查看答案
Big Data (大数据)📝 点击查看解析
大数据指规模庞大且复杂的数据集，需要数据仓储进行管理。Question 18 — Data Warehousing
The process of capturing, storing, and maintaining data is called ______.
📖 点击查看答案
Data warehousing (数据仓储)📝 点击查看解析
数据仓储是大数据处理中核心环节。Question 19 — Data Mining Applications
Name one business application of data mining.
📖 点击查看答案
- Recommending related products - Identifying customers for discounts 推荐相关产品；识别优惠客户📝 点击查看解析
数据挖掘常用于零售、金融、通信领域，提升客户价值与利润。Question 20 — Overfitting in Data Mining
Why is overfitting a risk in data mining?