1) A student wants to develop 3-sigma level variable control charts for the weight of firewood that comes in a box. Due to uneven shape of wood, weight of box varies a lot. Draw X-bar chart and R-chart using the table below. For both charts, calculate and show UCL, CL and LCL. Discuss your results. Weight in pounds from four samplings with sample size of three (n=3) are: Sampling 1 Sampling 2 Sampling 3 Sampling 4 18 38 22 26 26 30 28 20 26 26 26 26

1) A student wants to develop 3-sigma level variable control charts for the weight of firewood that comes in a box. Due to uneven shape of wood, weight of box varies a lot. Draw X-bar chart and R-chart using the table below. For both charts, calculate and show UCL, CL and LCL. Discuss your results. Weight in pounds from four samplings with sample size of three (n=3) are: Sampling 1 18 26 26 Sampling 2 Sampling 3 Sampling 4 38 22 26 30 28 20 26 26 26 Factors for 3 Sigma level (page 195 of textbook) Sanple Corral Limit Factor Size for Scarpe Men n A2 2 1.880 3 1.023 4 0.729 5 0.577 10 0.308 15 0.223 20 0.180 25 0.153 Control Limi Factor for Scample Range D3 D4 0 3.267 0 2.575 0 2.282 0 2.116 0.223 1.777 0.348 1.652 0.414 1.586 0.459 1.541