faithful {base} | R Documentation

## Old Faithful Geyser Data

### Description

The `faithful' data frame has 272 rows and 2 columns; the 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")

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