章节大纲

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  • 代表和分析分类数据

    What is Categorical Data?
    ::什么是分类数据?

    In science, there are so many ways to classify objects. Objects might be classified by age, gender, species, rock type, elemental composition, and more. Data that can be broken down into smaller groups is categorical data . Categorical data have numbers assigned to represent a group. For example, males may be recorded using the number 0 and females may be recorded using the number 1 when recording gender. Surveys are a commonly used method for collecting categorical data. Movie studios use screenings to show movies to select participants long before they are released in theaters. This process helps them collect data on how the movie will be received by audiences. What information would they collect and what numbers could they use to represent it?
    ::在科学中,有如此多的方法可以对物体进行分类。对象可以按年龄、性别、物种、岩石类型、元素构成等分类。可以细分为较小组的数据是绝对数据。分类数据指定了代表一个组的数字。例如,男性可以使用0号记录,女性在记录性别时可以使用1号记录。调查是收集绝对数据的一个常用方法。电影制片室在电影院放映电影之前很久就用筛选来选择参与者。这个过程有助于他们收集观众如何接收电影的数据。他们将收集哪些信息,他们可以使用哪些数字来代表它?

    How could collecting this information be helpful to a movie studio?
    ::如何收集这些信息 对电影制片厂有帮助?

      

    Close Encounters
    ::关闭对象

    Consider this data of  UFO sightings by continent between 1865 and 2004. To display this categorical information, we use a two-way table. A two-way table shows the frequency with which an event occurs based on two variables. In this case, those two variables are continent and whether or not the sighting took place before 1950. Each box is called a cell and the number inside represents the number of occurrences based on the matching column and row. The first cell shows the number of UFO sightings in North America before 1950.
    ::考虑1865年至2004年按大陆分列的UFO观测数据。为了显示这一绝对信息,我们使用双向表格。双向表格显示根据两个变量发生事件的频率。在此情况下,这两个变量是大陆,是否在1950年之前。每个框都称为单元格,里面的数字代表根据匹配的列和行的发生次数。第一个单元格显示1950年以前北美的UFO观测次数。

      Before 1950 1950 and After North America 17 125 South America 1 7 Europe 2 29 Africa 0 2 Asia 1 8 Australia 0 13
    ::1950-1950年之前和北美之后17125 南美洲17 欧洲229 非洲02 亚洲18 澳大利亚013

    Discussion Questions
    ::讨论问题 讨论问题

    1. What information jumps out when you look at this table?
      ::当你看这张桌子时,什么信息会跳出来?
    2. Is the only logical explanation for the high number of UFO sightings in North America after 1950 that aliens really enjoyed visiting North America during this time frame?
      ::1950年以后,在北美发现UFO的次数很多,为什么外星人在这段时间里真正享受到访问北美,这是否是唯一合乎逻辑的解释?

        

    Two-way tables make it easy to identify discrepancies in data. This can help to identify if the frequency of an event occurring is higher or lower for one group than another.
    ::双向表格便于识别数据差异,有助于确定某一组群发生事件频率高于或低于另一组群的频率。

     

    Categorical Data in Science
    ::科学分类数据

    A neurologist, a scientist who studies how the brain and nerve system interact with the body, conducted a 3-year study on college students in the US who received concussions. The purpose of this study was to examine concussions based on sport and gender. This data is displayed in the two-way table below. In addition to the frequencies based on the variables, you  can use this table to compute total frequencies. For example,  you can find the total number of concussions suffered by both male and female collegiate athletes that played by adding 75,734 and 75,082 to get 150,816.  You can find the total for each column and each row. Use the interactive below to find the totals for each row and column.
    ::一位研究大脑和神经系统如何与身体互动的神经学家,一位研究大脑和神经系统如何与身体互动的科学家,对接受脑震荡的美国大学生进行了为期三年的研究。这项研究的目的是研究基于体育和性别的脑震荡。这些数据显示在下面的双向表格中。除了基于变量的频率外,您还可以使用这张表格来计算总频率。例如,您可以找到男女合校运动员遭受的脑震荡的总数,即增加75,734和75,082人,以获得150,816美元。您可以找到每列和每行的总数。您可以使用下面的交互式表格来查找每行和每列的总数。

    INTERACTIVE
    Categorical Data
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    • Move the red points to see the total row and column totals.
      ::移动红点以查看总行和列总计。
    • Answer the questions by clicking the correct blue text.
      ::点击正确的蓝色文字回答问题。
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    Create a Table
    ::创建表格

    Now that  you know how to construct a two-way table and how to find the totals, create a two-way table from  the data-set from the 2014 Olympic Games held in Sochi, Russia.  The two-way table  you are going to create should display the number of medals with variables country and gender . For these games, the Russian men won 20 medals and the Russian women won 8 medals. The United States men won 13 medals and the United States women won 13 medals.
    ::现在,你知道如何建造双向桌和如何找到总数,从2014年俄罗斯索契奥运会的数据集中创建双向桌。你将要创建的双向桌应该显示有变数国家和性别的奖牌数量。俄罗斯男子赢得了20个奖牌,俄罗斯妇女赢得了8个奖牌。美国男子赢得了13个奖牌,美国妇女赢得了13个奖牌。

    Use the interactive below to construct the two-way table to display this data. Include a column and row at the end for totals.
    ::使用下面的交互数据来构造双向表格来显示此数据。在总和结尾处包含列和行。

    INTERACTIVE
    Create a Table for Medals
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    In the 2014 Winter Games in Sochi, the Russian men won 20 medals and the Russian women won 8 medals. The United States' men won 13 medals and the United States' women also won 13 medals.
    ::在2014年索契冬季奥运会上,俄罗斯男子赢得20个奖牌,俄罗斯妇女赢得8个奖牌,美国男子赢得13个奖牌,美国妇女也赢得13个奖牌。

    • Put these values and their totals into the table.
      ::将这些数值及其总数放在表格中。
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       Summary
    ::摘要

    • A two-way table  is used to show the frequencies between two variables. 
      ::双向表用于显示两个变量之间的频率。