# Investigation: How Faithful is Old Faithful?

## Summary

In this investigation, students examine data from the Old Faithful geyser in Yellowstone National Park and determine how predictable its eruptions actually are. The activity asks students to graph data in an appropriate fashion and then interpret those graphs in order predict how long one would have to wait for the next eruption. The activity also touches on how to determine the reliability of this prediction.

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## Learning Goals

• Build skills and gain experience in analyzing and interpreting real geologic data.

## Context for Use

This activity is meant to follow a discussion of how geysers work, so that students have a basis for conjecture on the source of the variability in the times between eruptions. See the course description, including links to all of the other teaching activities for this course on the Geology of the National Parks.

## Description and Teaching Materials

Old Faithful Activity Sheet (Acrobat (PDF) 118kB May5 04)
Excel data file (Excel 27kB Mar15 04)
MiniTab data file ( 11kB Mar15 04)

## Teaching Notes and Tips

• For parts 1-4, split the data file into small pieces (10-20 data points each) and give each student one piece. They should graph, analyze and make predictions based on it. Then have them trade data sets several times with neighboring students and repeat to get a broader picture.
• Questions to help promote statistical thinking in the students are listed in the Shaughnessy and Pfannkuch article referenced below. Questions are broken out by the part of the exercise where they are appropriate.

## Assessment

The activity report can be completed individually or as a group and should be a summary of the Investigation Question, the process for answering it and what that answer was. The report should be concise (less that 2 pages, typed) and should answer each of the major questions asked in the activity sheet.

## References and Resources

Shaughnessy and Pfannkuch, 2002 . How Faithful is Old Faithful? Statistical Thinking: A Story of Variation and Prediction. Mathematics Teacher, v. 95, n. 4, pp. 252-259.

Fournier, Robert (1969). Old Faithful: A Physical Model. Science, v. 163, pp. 304-305.

Azzalini, A. and A. W. Bowman (1990). A Look at Some Data on the Old Faithful Geyser. Applied Statistics, v. 39, n. 3, pp. 357-365.