BOX Subcommand (IGRAPH command)

BOX creates a boxplot, sometimes called a box-and-whiskers plot, showing the median, quartiles, and outlier and extreme values for a scale variable. The interquartile range (IQR) is the difference between the 75th and 25th percentiles and corresponds to the length of the box.

The following keywords are available:

OUTLIERS. Indicates whether outliers should be displayed. Outliers are values between 1.5 IQR’s and 3 IQR’s from the end of a box. By default, the boxplot displays outliers (ON).

EXTREME. Indicates whether extreme values should be displayed. Values more than 3 IQR’s from the end of a box are defined as extreme. By default, the boxplot displays extreme values (ON).

MEDIAN. Indicates whether a line representing the median should be included in the box. By default, the boxplot displays the median line (ON).

BOXBASE. This keyword is no longer supported and is ignored.

WHISKER. Controls the appearance of the whiskers. Whiskers can be straight lines (LINE) or end in a T-shape (T). FANCY is no longer supported and is ignored.

CAPWIDTH(pct). Controls the width of the whisker cap relative to the corresponding box. Pct equals the percentage of the box width. The default value for pct is 45.

Example

IGRAPH
 /X1=VAR(region) TYPE=CATEGORICAL
 /Y=VAR(sales96) TYPE=SCALE
 /COORDINATE=HORIZONTAL
 /BOX OUTLIERS=ON EXTREME=ON MEDIAN=ON WHISKER=LINE.
  • X1 assigns the variable region to the X1 axis.
  • Y assigns the variable sales96 to the range axis.
  • COORDINATE positions the range axis along the horizontal dimension.
  • BOX creates a boxplot. The outliers and extreme vales are shown. In addition, a line representing the median is added to the box.
  • WHISKER yields whiskers ending in a straight lines.

Example

IGRAPH
 /X1=VAR(region) TYPE=CATEGORICAL
 /Y=VAR(sales96) TYPE=SCALE
 /X2=VAR(division) TYPE=CATEGORICAL
 /COORDINATE=THREE
 /BOX OUTLIERS=OFF EXTREME=ON MEDIAN=OFF WHISKER=T.
  • X2 adds a third dimension, corresponding to division, to the boxplot in the previous example.
  • COORDINATE indicates that the chart displays the third dimension.
  • BOX creates a boxplot without outliers or a median line. Extreme values are shown.