Factors for Calculating Three-Sigma Limits for the * Chart and R-Chart Factor for UCL Factor for Factor for Size of and LCL for LCL for UCL for Sample x-bar-Charts A-Charts A-Charts A2 D3 D4 1.880 3.267 1.023 2.575 0.725 2.282 0.57 2.115 10.483 0 2.004 0.419 0.07 6 1.924 8 0.373 0.136 1.864 0.337 0.184 1.816 10 0.308 0.223 1.777 Source: 1950 ASTM Manual on Quality Control of Materials, copyright American Society for Testing Materials. Reprinted with permission. Thermostats are subjected to rigorous testing before they are shipped to air conditioning technicians around the world. Results from the last five samples are shown in the table. Calculate control limits for a chart that will monitor process consistency. The correct control limits as (LCL,UCL) are: Sample 1 Sample 2 Sample 3 Sample 4 Sample 5 Unit 1 73.50 70.80 72.20 73.60 71.00 Unit 2 71.30 64.33 73.10 72.70 72.20 Unit 3 68.27 72.60 71.90 63.16 75.11 Unit 4 71.10 65.71 70.30 74.20 73.60 Unit 5 61.25 70.70 62.78 68.22 71.10 Unit 6 70.80 70.70 70.70 73.50 71.10 O A) (0.00,16.12) O B) (0.00,6.03) ( C) (1.62, 19.80) O D) (0.00,5.37) O E) (-5.37,5.37) ( F) (0.00, 18.43)