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. Draw and R Chart and an x-bar chart. Based on the charts, is the process under control?
Unit #Sample 1Sample 2 Sample 3 Sample 4 Sample 5
1 73.5 70.8 72.2 73.6 71.0
2 71.3 71.0 73.1 72.7 72.2
3 70.0 72.6 71.9 72.4 73.3
4 71.1 70.6 70.3 74.2 73.6
5 70.8 70.7 70.7 73.5 71.1