faithful                package:base                R Documentation

Old Faithful Geyser Data

Description:

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

Usage:

     data(faithful)

Format:

     A data frame with 272 observations on 2 variables.

       [,1]  eruptions  numeric  Eruption time in mins
       [,2]  waiting    numeric  Waiting time to next eruption

Details:

     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 eruptions times, see the example below.

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

Source:

     W. Härdle.

References:

     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.

See Also:

     'geyser' in package 'MASS' for the Azzalini-Bowman version.

Examples:

     data(faithful)
     f.tit <-  "faithful data: Eruptions of Old Faithful"

     ne60 <- round(e60 <- 60 * faithful$eruptions)
     all.equal(e60, ne60)             # relative diff. ~ 1/10000
     table(zapsmall(abs(e60 - ne60))) # 0, 0.02 or 0.04
     faithful$better.eruptions <- ne60 / 60
     te <- table(ne60)
     te[te >= 4]                      # (too) many multiples of 5 !
     plot(names(te), te, type="h", main = f.tit, xlab = "Eruption time (sec)")

     plot(faithful[, -3], main = f.tit,
          xlab = "Eruption time (min)",
          ylab = "Waiting time to next eruption (min)")
     lines(lowess(faithful$eruptions, faithful$waiting, f = 2/3, iter = 3),
           col = "red")

