Old Faithful and Histogram Bin Size

Histogram are a remarkable way to "see" data. And, carefully constructed, a histogram can reveal a lot of information. Nevertheless, some care must also be taken when making a histogram. In particular, how the bin size is selected makes a big difference.

An Example Old Faithful Eruption Times

Look at the histogram below. It shows the lengh of eruptions (in minutes) of Old Faithful. Notice that you can adjust the bin width by dragging on the marker of the bin width scale. Play around with it and see which bin width gives you the best "view" of the data.

When you are done here, you can

try this with other data
go BACK to (none)

References: For more information on Old Faithful eruptions and possible explanations for what you see in this hitogram, see the following links:

WyoJones' Yellowstone Geyser Pages has info about Old Faithful, including photos and many links to articles, data, etc.
One of the sample data sets in WebStat (a Java statistical package you can run from your brouser) contains data from various measurements of Old Faithful eruptions, including both length of eruption and interval between eruptions.

The applet used on this page was made by

R. Webster West
Department of Statistics
University of South Carolina
Columbia, SC 29208
Office Phone: (803) 777-3792
Fax: (803) 797-1822
E-mail: west@stat.sc.edu

See http://www.stat.sc.edu/~west/javahtml/Histogram.html for more information, including how to put this applet on your own pages with your own data.

This page maintained by:
Randall Pruim
Department of Mathematics and Statistics
Calvin College
rpruim@calvin.edu

Last Modified: Sunday, 04-Mar-2001 00:35:31 EST