HISTOGRAM Subcommand (IGRAPH command)

HISTOGRAM creates a histogram element in a chart, corresponding to the X1, X2, and Y axis assignments. Horizontal or vertical orientation is specified by the COORDINATE subcommand. A histogram groups the values of a variable into evenly spaced groups (intervals or bins) and plots a count of the number of cases in each group. The count can be expressed as a percentage. Percentages are useful for comparing datasets of different sizes. The count or percentage can also be accumulated across the groups.

  • $COUNT or $PCT must be specified on the Y subcommand.

The following keywords are available:

SHAPE. Defines the shape of the histogram. Currently, the only value for SHAPE is HISTOGRAM.

CUM. Specifies a cumulative histogram. Counts or percentages are aggregated across the values of the domain variables.

X1INTERVAL. Intervals on the X1 axis can be set automatically, or you can specify the number of intervals (1 to 250) along the axis (NUM) or the width of an interval (WIDTH).

X2INTERVAL. Intervals on the X2 axis can be set automatically, or you can specify the number of intervals (1 to 250) along the axis (NUM) or the width of an interval (WIDTH).

CURVE. Superimposes a normal curve on a 2-D histogram. The normal curve has the same mean and variance as the data.

X1START. The starting point along the X1 axis. Indicates the percentage of an interval width above the minimum value along the X1 axis at which to begin the histogram. The value can range from 0 to 99.

X2START. The starting point along the X2 axis. Indicates the percentage of an interval width above the minimum value along the X2 axis at which to begin the histogram. The value can range from 0 to 99.

Example

IGRAPH
 /X1=VAR(sales96) TYPE=SCALE
 /Y=$count
 /Histogram SHAPE=HISTOGRAM CURVE=ON X1INTERVAL WIDTH=100.
  • Histogram creates a histogram of sales96. The sales96 intervals are 100 units wide.
  • CURVE superimposes a normal curve on the histogram.