| % File src/library/datasets/man/morley.Rd |
| % Part of the R package, https://www.R-project.org |
| % Copyright 1995-2014 R Core Team |
| % Distributed under GPL 2 or later |
| |
| \name{morley} |
| \docType{data} |
| \alias{morley} |
| \title{Michelson Speed of Light Data} |
| \description{ |
| A classical data of Michelson (but not this one with Morley) on |
| measurements done in 1879 on the speed of light. The data consists of |
| five experiments, each consisting of 20 consecutive \sQuote{runs}. |
| The response is the speed of light measurement, suitably coded |
| (km/sec, with \code{299000} subtracted). |
| } |
| \usage{ |
| morley |
| } |
| \format{ |
| A data frame with 100 observations on the following 3 variables. |
| \describe{ |
| \item{\code{Expt}}{The experiment number, from 1 to 5.} |
| \item{\code{Run}}{The run number within each experiment.} |
| \item{\code{Speed}}{Speed-of-light measurement.} |
| } |
| } |
| \details{ |
| The data is here viewed as a randomized block experiment with |
| \sQuote{experiment} and \sQuote{run} as the factors. \sQuote{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. |
| } |
| \note{ |
| This is the same dataset as \code{michelson} in package |
| \CRANpkg{MASS}. |
| } |
| \source{ |
| A. J. Weekes (1986) |
| \emph{A Genstat Primer}. |
| London: Edward Arnold. |
| |
| S. M. Stigler (1977) |
| Do robust estimators work with real data? |
| \emph{Annals of Statistics} \bold{5}, 1055--1098. (See Table 6.) |
| |
| A. A. Michelson (1882) |
| Experimental determination of the velocity of light made at the United |
| States Naval Academy, Annapolis. |
| \emph{Astronomic Papers} \bold{1} 135--8. |
| U.S. Nautical Almanac Office. (See Table 24.) |
| } |
| \examples{ |
| require(stats); require(graphics) |
| michelson <- transform(morley, |
| Expt = factor(Expt), Run = factor(Run)) |
| xtabs(~ Expt + Run, data = michelson) # 5 x 20 balanced (two-way) |
| plot(Speed ~ Expt, data = michelson, |
| main = "Speed of Light Data", xlab = "Experiment No.") |
| fm <- aov(Speed ~ Run + Expt, data = michelson) |
| summary(fm) |
| fm0 <- update(fm, . ~ . - Run) |
| anova(fm0, fm) |
| } |
| \keyword{datasets} |