**次数分布图(Frequency Distribution Graph)**

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**一、直方图（histogram），棒图（bar graph）**
  *直方图，适用于等距或等比数据，横轴表示数据X，纵轴表示次数f，以数据间的直方条表示次数分布。直方条的高度表示次数，宽度表示精确区间。
  *当数据是命名或顺序测度时，则用棒图表示次数分布，每个直方条之间留有一定的空间。
  *A histogram is suitable for interval or ratio data, where the horizontal axis represents data X and the vertical axis represents frequency f. The distribution of frequency is represented by the histogram between the data. The height of the histogram represents frequencies, and the width represents the exact interval.
  *When the data is a nominal or ordinal scale, a bar graph is used to represent the degree distribution, leaving a certain space between each histogram.


**二、折线图（frequency distribution polygon）**
  *折线图，也叫次数分布多边图，适用于等距或比例型数据，将每个X值对应的次数点连成折线，以线条表示数据的变化趋势。
  *A line graph, also known as a frequency distribution polygon, is suitable for interval or ratio data. It connects the frequency points corresponding to each X value into a line and represents the trend of data changes with lines.

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**三、茎叶图（stem and leaf display）**
  *茎叶图，可以实现不用分组次数分布表来表示众多的数据。
  *在正式的报告中，一般不使用茎叶图。
  *A stem and leaf display represents a large amount of data without using a grouped frequency tables.
  *Stem and leaf display is generally not used in formal report.