A data set from Oehlert (2000) \emph{A First Course in Design and Analysis of Experiments}, New York: W. H. Freeman. Data originally from Chu, Y. C. (1970). Comparison of {\em in vivo\/} and {\em vitro\/} inhibition of {ATP}ases by the insecticide {C}hlordane. Master's thesis, University of Minnesota, St. Paul, MN. Percentage change in Na-K-ATPase activity in coxal muscles of cockroaches after treatment with chlordane.