章节大纲

  • Learning about Lefties
    ::学习左撇子

    Visual representation showing a diverse group as a sample and a subset of left-handed individuals.
    Left-handed people as part of the total population

    Y ou may have explored ways to compare data sets in other lessons. Here, you will begin learning how to collect samples of the sort of data used to create those sets.
    ::您可能已经探索了比较其他课程中数据集的方法。 在这里, 您将开始学习如何收集用于创建这些数据集的数据的样本 。

    Samples are used by media outlets to predict elections before they happen, by scientists to study how treatments affect people to ensure safety, by sports leagues to determine how a rule change will affect the sport and much more.
    ::媒体机构使用样本来预测选举发生之前的选举,科学家使用样本来研究治疗如何影响人们确保安全,体育联盟则用样本来确定规则的改变如何影响运动,甚至影响更多。

    For example , you can use sampling to answer questions like:
    ::例如,您可以使用抽样回答问题,例如:

    • How many people in the world are left-handed?
      ::世界上有多少人是左撇子?
    • What percentage of people in a city support the local baseball team?
      ::城市里有多少人支持当地棒球队?
    • Which candidate is most likely to win an election?
      ::哪个候选人最有可能赢得选举?

    Discussion Questions
    ::讨论问题 讨论问题

    1. If you want to know how many people in a class are left-handed, how would you obtain these results?
      ::如果你想知道一个班里有多少人是左撇子, 你会如何获得这些结果?
    2. If you want to know how many people in a school are left-handed how would you obtain these results?
      ::如果你想知道学校里有多少人是左撇子, 你如何获得这些结果?
    3. If you want to know how many people in a city are left-handed, how would you obtain these results?
      ::如果你想知道一个城市里有多少人左撇子,你如何获得这些结果?

    Sampling
    ::抽样抽样

    Sampling is the practice of using data obtained from a group to represent a population . A population is a group of objects with a common characteristic. The group selected from the population is called a sample . By studying small groups of a larger population,  you can identify trends that might apply to the entire population.  Here and in other lessons on sampling,   you will explore what makes a good sample and how it can be used to make estimates about large populations.
    ::抽样是使用从一个群体获得的数据来代表一个人口的做法。人口是一个具有共同特征的物体组。从人口中选定的群体称为抽样。通过研究较大人口组的小群体,你可以确定可能适用于整个人口组的趋势。在这里和关于抽样的其他教训中,你将探讨什么是一个很好的样本,以及如何利用它来估计大量人口。

    Example
    ::示例示例示例示例

    Henry is a baseball fan living in New York City. New York has two baseball teams: the Mets and the Yankees. Henry wants to know what percentage of people living in New York City support the Yankees and what percentage support the Mets. To answer this question, Henry asked 300 random New Yorker City residents who their favorite baseball team was. He recorded his results and found that 45% of New Yorkers preferred the Mets and 43% preferred the Yankees.
    ::亨利是一个棒球球迷,住在纽约市。纽约有两个棒球队:大都会和洋基队。亨利想知道在纽约市生活的人中支持洋基队的比例是多少,支持美基队的比例是多少。为了回答这个问题,亨利问300个纽约市居民他们最喜欢的棒球队是谁。他记录了他的成绩,发现45%的纽约人更喜欢美球队,43%的人更喜欢洋基队。

    What is the population? What is the sample?
    ::人口是多少?抽样是多少?

    In this example, the population was every resident in New York City. However, Henry couldn't interview every New York City resident so he had to take a sample . The size of Henry's sample was 300 because this was the number of New York City residents he surveyed. In the coming sections,  you will learn how to conduct surveys, remove bias , and analyze datasets.
    ::在这个例子中,人口是纽约市的每一个居民。然而,亨利无法采访纽约市的每一个居民,所以他不得不抽取样本。亨利的样本是300个,因为这是他所调查的纽约市居民人数。在接下来的几节中,你将学会如何进行调查,消除偏见,分析数据集。

    Discussion Question
    ::讨论问题

    Come up with a question of your own that could be answered through sampling. What would the population be? What would the sample be? How would you obtain the results?
    ::想想你自己的问题,这个问题可以通过抽样回答。人口会是什么?抽样会是什么?你将如何获得结果?

    Popular Populations 
    ::民众人口

    To take an appropriate sample,  you first need to understand what a population is. Populations are often associated with people living in a certain location. For example, the population of Canada is 36.71 million people. However, the term population is used to describe any group of objects with a similar characteristic. In this example, that characteristic is  being   a  Canadian. The term population can also be used to describe animals, plants, rocks, colors, etc. The size of a population is the number of objects that make up the population.
    ::为了进行适当的抽样调查,您首先需要了解人口是什么。 人口通常与居住在某个地方的人有关,例如,加拿大人口为3 671万人,然而,用人口一词来描述具有类似特征的任何一类物体。在这个例子中,这个特征是加拿大人。人口也可以用来描述动物、植物、岩石、颜色等。人口规模是构成人口的物体数量。

    Discussion Question
    ::讨论问题

    Earlier we were asked to determine the number of people in the world that are left-handed. What population could help us determine this?
    ::早些时候,有人要求我们确定世界上左撇子的人数,哪些人能帮助我们确定这一点?

    Simple Samples
    ::简单样本

    Now that  you understand populations,  you can take samples from them. Asking every single voter in a state who they are going to vote for, or counting every single animal a country is a very tall task. The solution to this problem is to use a sample. By taking a group of objects from a population,  you can use the group to estimate traits of the population as a whole.
    ::既然您了解了人群, 您可以从人群中提取样本。 询问每个选民在某个州将投票支持谁, 或者计算每个动物, 一个国家是一个非常艰巨的任务。 解决这个问题的办法是使用样本。 通过从人群中取取一组物体, 您可以使用该人群来估计整个人群的特征 。

    Use the questions below to practice determining which option represents a sample from the populations given.
    ::使用以下问题来确定哪一种选择是所给人口的抽样。

    Discussion Question
    ::讨论问题

    Sarah and Rebecca want to know what proportion of human beings are over 7 feet tall. What is the population? Sarah believes this question could be answered using everyone in her town as a sample. Do you agree?
    ::Sarah和Rebecca想知道,有多少人超过7英尺高。人口是多少?Sarah认为这个问题可以用她镇上的每个人作为样本来回答。你同意吗?

      Summary
    • A population is a discrete group of objects with a common characteristic.
      ::一个群是一个由具有共同特征的物体组成的离散群。
    • A sample is a group selected from a population.
      ::样本是从人群中挑选出来的一组群体。
    • Sampling is the practice of using data obtained from a group to represent a population.
      ::抽样是使用从一个群体获得的数据来代表一个人口的做法。