Software and activities for teaching probability via simulations

Prob Sim was a Macintosh (Classic) program from the 1990s with accompanying instructional activities designed for teaching probability via simulations in grades 6-13.

To model a probabilistic situation, you:

  • construct a "Mixer" containing the elementary events of interest;
  • sample from the Mixer after specifying replacement options, sample size, and number of repetitions; and
  • search for or count specified events of interest in that and subsequent samples.

The program made the last step especially easy. Once analyzes had been conducted on one sample, you could press a button to see the results of the same analyses performed on a new random sample.

Prob Sim was especially useful for mathematics teachers striving to teach students probability in line with recommendations offered by the National Council of Teachers of Mathematics in their Principles and Standards for School Mathematics.

Also included with the software was a User's Guide and Instructional Activities.

System Requirements

Prob Sim was written in 1992, so you can run in on:

  • any Macintosh computer with 1MB of RAM or more, with
  • MacOS 6.0.5 - 9.2.2, or MacOS X with the Classic environment installed, and a
  • 68000 or PowerPC processor (not an Intel processor)

We have tested it on recent versions of Macintosh's operating system (including OS X 10.4) and it appears to work well. But we cannot guarantee that it will continue to do so, and we are not planning any future updates.


Prob Sim Software License

You are free to load Prob Sim onto as many machines as you like and use it freely. However, you cannot resell it or incorporate any parts of it, including the documentation or activities, into another product or publication without written permission.

Prob Sim is provided "as is" without any implied warranty. Users must assume complete responsibility for any errors or data loss while using the program.

Technical assistance, other than what is in the written documentation, is not available for Prob Sim. You are strictly on your own. (We should add that we have heard of no problems using Prob Sim.)

Download Form

To download this software, please read and complete this form.

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Click here if you have read and agree with the conditions in the license.

If you experience problems with this form, please contact


Prob Sim was developed by:

Clifford Konold and Craig D. Miller
Scientific Reasoning Research Institute
University of Massachusetts, Amherst, MA, USA

The development of Prob Sim was funded by a grant from the National Science Foundation (grant no. MDR-8954626). The Prob Sim software and related materials are copyrighted 1992-2003 by Clifford Konold.