# Mcelhoe And Conner 1986 Use An Instrument Called A Visiplume To Measure Ultraviolet 1620842

McElhoe and Conner (1986) use an instrument called a “Visiplume” to measure ultraviolet light. By comparing absorption in clear air and absorption in polluted air, the concentration of SO2 in the polluted air can be estimated. The EPA has a standard method for measuring SO2, and we wish to compare the two methods across a range of air samples. The recorded response is the ratio of the Visiplume reading to the EPA standard reading. There were six observations on coal plant number 2: .950, .978, .762, .733, .823, and 1.011. If we make the null hypothesis be that the Visiplume and standard measurements are equivalent (and the Visiplume and standard labels are just labels and nothing more), then the ratios could (with equal probability) have been observed as their reciprocals. That is, the ratio of .950 could with equal probability have been 1/.950 = 1.053, since the labels are equivalent and assigned at random. Suppose we take as our summary of the data the sum of the ratios. We observe .95 + … + 1.011 = 5.257. Test (using randomization methods) the null hypothesis of equivalent measurement procedures against the alternative that Visiplume reads higher than the standard. Report a p-value.

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