If a scientist wanted to compare air quality throughout the United States but was unable to test the air in every city, the scientist could compare the air quality in a
Blank
______ or subset of cities.

Question

If a scientist wanted to compare air quality throughout the United States but was unable to test the air in every city, the scientist could compare the air quality in a 
Blank
______ or subset of cities.

BlackTom AI · Accepted Answer

A sample is a subset chosen from a larger population to make inferences about that population, so "sample" is the correct choice.

1. Relevant knowledge points and concepts
- Population: the full set of items of interest (here, all cities in the United States).
- Sample: a subset of the population selected for measurement.
- Representativeness and sampling methods (random, stratified, systematic) determine how well a sample reflects the population.
- Bias and sampling error: nonrepresentative samples lead to incorrect conclusions.
- Distinction from "model" (a simplified representation or simulation) and "mean" (a numerical average computed from data).

2. Step-by-step reasoning
- The scientist cannot measure air in every city (the population is too large).
- To compare air quality nationally, the scientist must measure air in some cities and use those results to estimate national conditions.
- The appropriate technical term for that subset of cities is "sample."
- The scientist should select a sample in a way that minimizes bias (for example, random or stratified sampling by region and city size) so that results generalize to the whole country.

3. Calculations / intermediate steps
- No numerical calculation is required here. The logical step is: Population (all U.S. cities) → choose a subset with proper sampling design → subset = sample → analyze sample to estimate population air quality.

4. Why the correct answer is correct
- "Sample" matches the definition: a subset of cities used to estimate characteristics of the whole population. It directly fills the blank: "a sample or subset of cities."

5. Why other options are incorrect
- "Model" is a theoretical or mathematical representation (e.g., a simulation of pollutant dispersion), not the physical subset of cities measured.
- "Mean" is a statistic (average) calculated from data, not the subset itself; you compute a mean from a sample, but the mean is not the sample.

6. Conclusion
The best choice is "sample," which matches the provided answer.

If a scientist wanted to compare air quality throughout the United States but was unable to test the air in every city, the scientist could compare the air quality in a Blank ______ or subset of cities.单项选择题

类似问题

Attribute measurement requires a much larger sample size than variable measurement to obtain the same amount of statistical information.

What is a subset of objects taken from population?

What was the world's first widely adopted biodiversity policy?

The aim of the Paris Agreement is to ensure that the earth’s preindustrial temperature is not exceeded by more than º Celsius.

The IPCC's mission is to Blank ______.

Why have most international agreements for environmental protection been based on the honor system?

As was exhibited with the Montreal Protocol and the encouragement of reduced CFC production, trade can be an effective tool to compel compliance with international treaties.

The Stockholm Declaration and UNEP were the result of the Blank ______ first conference on the Human Environment in 1972.

更多留学生实用工具

智能学习助手

风格化写作助手

论文查重助手

文献引用助手

课堂转译助手

课堂笔记助手

Quiz搜索助手

学校历年真题

智能刷题助手

智能匹配练习

希望你的学习变得更简单