Bath concentrations are measured hourly in chemical process. Data(in ppm) for last 32 hours are shown in below data (please read down the columns to understand the order that the measurements were taken.) The process target is ?0=175
160 186 190 206
158 195 189 210
150 179 185 216
151 184 182 212
153 175 181 211
154 192 180 202
158 186 183 205
162 197 186 197
a) Estimate the process standard deviation.
b) Set up and apply an EWMA control chart to the data usig lambda = 01 and L = 27
c) Plot the EWMA chart and interpret the chart