A valve manufacturer produces a butterfly valve composed of

A valve manufacturer produces a butterfly valve composed of two semicircular plates on a common spindle that is used to permit flow in one direction only (seen here: http://en.wikipedia.org/wiki/Butterfly_valve). The manufacturer produces valves in five different factories: Pawhuska, Barnsdall, Wynona, Fairfax, and Shidler. The precision of the valve, measured as the magnitude of deviation from the specification in 1/100 inch, is provided (In the in the table below) for a random sample of valves produced at each factory. Is there a difference in the valves being produced at the facilities, as measured by precision? If so, use the Tukey test to further analyze the factories, highlighting the best performing and worst performing factories. Use RCode.

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