faithful          package:datasets          R Documentation(latin1)

_O_l_d _F_a_i_t_h_f_u_l _G_e_y_s_e_r _D_a_t_a

_D_e_s_c_r_i_p_t_i_o_n:

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

_U_s_a_g_e:

     faithful

_F_o_r_m_a_t:

     A data frame with 272 observations on 2 variables.

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

_D_e_t_a_i_l_s:

     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.

_S_o_u_r_c_e:

     W. Härdle.

_R_e_f_e_r_e_n_c_e_s:

     Haerdle, 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.

_S_e_e _A_l_s_o:

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

_E_x_a_m_p_l_e_s:

     require(stats); require(graphics)
     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")