faithful = pd.read_csv(DATA_DIR / "faithful.csv")

Old Faithful Geyser Data


Waiting time between eruptions and the duration of the eruption for the Old Faithful geyser in Yellowstone National Park, Wyoming, USA.


A data frame with 272 observations on 2 variables.

Column Description
eruptions Eruption time in mins
waiting W aiting time to next eruption (in mins)


A closer look at faithful.eruptions reveals that these are heavily rounded times originally in seconds, where multiples of 5 are more frequent than expected under non-human measurement. For a better version of the eruption times, see the example below.

There are many versions of this dataset around: Azzalini and Bowman (1990) use a more complete version.


W. Härdle.


Härdle, W. (1991) Smoothing Techniques with Implementation in S. New York: Springer.

Azzalini, A. and Bowman, A. W. (1990). A look at some data on the Old Faithful geyser. Applied Statistics 39, 357–365.