solution

A small manufacturer of metal ring seals for aircraft engines has been asked by its major customer to implement statistical process control (SPC). One major type of ring requires cutting a one- eighth inch wide slot using a milling machine. The following six samples of five observations each, taken every half hour, are width of the slots (in inch) made by the milling machine on the rings. 1 2 3 4 5 6 0.1261 0.1259 0.1239 0.1225 0.1259 0.1255 0.1253 0.1263 0.1265 0.1249 0.1243 0.1273 0.1245 0.1247 0.126 0.1265 0.1242 0.1245 0.1249 0.124 0.1257 0.1248 0.1257 0.1268 0.1248 0.1251 0.1243 0.1256 0.1251 0.1263 a. Set up the sample mean and range control charts for this operation. b. Is this process in control? c. The seventh sample contains the following values: 0.114,0.1242, 0.1285, 0.1252, and 0.1265. Using the control charts from part (a), is the process still in control?