Use the Histogram command to plot the frequency distribution of the amplitudes of a selected record. The Histogram command creates a new document window.
DPlot initially suggests a sampling interval such that:
k = number of sampling intervals
n = total number of samples
This is the sampling interval suggested by H.A. Sturges in "The choice of a class interval," Journal of American Statisticians Association, vol. 21, 65-66, 1926
Interval between eruptions of Old Faithful measured in 2006. Source: http://www.geyserstudy.org/geyser.aspx?pGeyserNo=OLDFAITHFUL
The Histogram command with an interval of 5 minutes (expressed as either 0:05 or 0.083333 hours) yields:
The mean, standard deviation, and skewness properties are calculated automatically by the Histogram command. Skewness is a measure of the tendency of deviations from the mean to be larger in one direction:
Right-click on the plot and select Bar Chart Options to change various aspects of the plot. For example the following plot was created by checking the "Percentage labels", "Labels outside bars", and "Shaded bars" boxes. The extents of the graph were changed with the Extents/Intervals/Size command on the Options menu.
As shown in this graph, 74.9% of Old Faithful's eruptions occurred in intervals between 1:25 and 1:40, and 91% of the eruptions occurred in intervals between 1:20 and 1:45 - presumably a reason for the geyser's name.
Related macro commands