1- 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. Use the X and R charts to determine if the process is under control. Observation 1 2 3 4 5 Sample 1 73.570.872.273.671.0 Sample 2 71.371.073.172.772.2 Sample 3 70.074.673.972.4 75 Sample 4 71.170.670.374.273.6 Sample 5 73.9 74.7 74.9 74.5 75.1