what is the correct answer? What do you see on the range chart?

Return to the chart in Figure 11-8. Is this process stable? Explain. Don't forget to look at the range

Not Stable, 3 and 8 are out of the control. (explain more)

Chapter 11 . Statistically Based Quality Improvement for Variables 289 Variables Control Chart (x and R) Part number Chart number Operation (process) Part name (product) Grommet Operator Specification limits 24-36 Unit of measure Zero equals .0001 Machine Gauge Date Time 1 2429 38 24 33 28 30 19 24 26 25 28 31 30 26 24 25 26 27 28 24 18 29 29 2014 2 27 30 42 28 36 28 28 26 27 27 26 24 26 31 25 36 35 30 31 33 24 42 30 30 36 25 3 28 29 36 27 31 28 27 23 33 38 27 29 38 33 24 24 25 28 29 30 32 36 31 31 34 36 4 33 31 35 32 28 28 26 22 28 26 28 26 22 28 26 28 30 24 32 36 30 24 32 36 36 35 32 33 34 32 30 28 32 35 5 Sum 112 119 151 111 128 112 111 90 112 117 106 111 119 126 111 120 120 116 120 125 112 126 118 122 110 Average, X 28 2975 37.75 27.75 32 28 27.75 22.5 28 29.25 265 27.75 29.75 31.5 27.75 30 30 29 30 31.25 28 31.5 29.5 30.5 27.5 Range, R 9 9 2 7 8 8 0 4 7 9 12 3 6 14 3 12 12 10 6 6 6 8 24 6 3 16 22 Notes Sample measurements 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 JA 37 36 UCL=35578 35 34 33 32 31 30 29 28 27 Averages 25 24 LCL =22922 23 22 UCLR=19.808 28 Ranges NORINO FIGURE 11-8 Completed x and R Chart