A data set from Oehlert (2000) \emph{A First Course in Design and Analysis of Experiments}, New York: W. H. Freeman. Data originally from McElhoe, H. B. and W. D. Conner (1986). ``Remote measurement of sulfur dioxide emissions using an ultraviolet light sensitive video system.'' {\em Journal of the Air Pollution Control Association\/}~{\em 36}, 42--47. These six observations are the ratios of the SO2 measurements provided by the Visiplume instrument and a standard method taken at a coal fired power plant.