Old Faithful Geyser in Yellowstone National Park, Wyoming, derives its name and its considerable fame from the regularity (and beauty) of its eruptions. As they do with most geysers in the park, rangers post the predicted tiems of eruptions on signs nearby and people gather beforehand to witness the show. R.A. Hutchinson, a park geologist, collected measurements of the eruption durations (X, in minutes) and the subsequent intervals before the next eruption (Y, in minutes) over an 8--day period.
Weisberg, S. (1985). Applied Linear Regression, John Wiley \& Sons, New York, p. 231.
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