Unit #	Sample 1	Sample 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

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 (the above measures represent temperature readings in Fahrenheit). Calculate control limits for a chart that will monitor whether the variability of the process is under control (R chart). The (3sigma) UCL for this control chart is ______. Pick the closest answer.

Options:

68

70

72

74

76