Wire electrical-discharge machining (wedm) is a process used to manufacture conductive hard metal components. it uses a continuously moving wire that serves as an electrode. coating on the wire electrode allows for cooling of the wire electrode core and provides an improved cutting performance. the article “high- performance wire electrodes for wire electrical- discharge machining—a review” (j. of engr. manuf., 2012: 1757–1773) gave the following sample observations on total coating layer thickness (in mm) of eight wire electrodes used for wedm:
21 16 29 35 42 24 24 25
calculate a 99% cl for standard deviation of the coating layer thickness distribution. is this interval valid whatever the nature of the distribution? explain.