morley               package:datasets               R Documentation

_M_i_c_h_a_e_l_s_o_n-_M_o_r_l_e_y _S_p_e_e_d _o_f _L_i_g_h_t _D_a_t_a

_D_e_s_c_r_i_p_t_i_o_n:

     The classical data of Michaelson and Morley on the speed of light.
     The data consists of five experiments, each consisting of 20
     consecutive 'runs'.  The response is the speed of light
     measurement, suitably coded.

_U_s_a_g_e:

     morley

_F_o_r_m_a_t:

     A data frame contains the following components:

     '_E_x_p_t' The experiment number, from 1 to 5.

     '_R_u_n' The run number within each experiment.

     '_S_p_e_e_d' Speed-of-light measurement.

_D_e_t_a_i_l_s:

     The data is here viewed as a randomized block experiment with
     'experiment' and 'run' as the factors.  'run' may also be
     considered a quantitative variate to account for linear (or
     polynomial) changes in the measurement over the course of a single
     experiment.

_S_o_u_r_c_e:

     A. J. Weekes (1986) _A Genstat Primer_. London: Edward Arnold.

_E_x_a_m_p_l_e_s:

     require(stats); require(graphics)
     morley$Expt <- factor(morley$Expt)
     morley$Run <- factor(morley$Run)

     xtabs(~ Expt + Run, data = morley)# 5 x 20 balanced (two-way)
     plot(Speed ~ Expt, data = morley,
          main = "Speed of Light Data", xlab = "Experiment No.")
     fm <- aov(Speed ~ Run + Expt, data = morley)
     summary(fm)
     fm0 <- update(fm, . ~ . - Run)
     anova(fm0, fm)