operations management question

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. Draw and R Chart and an x-bar chart.  Based on the charts, is the process under control? (20 Points)

 

 

Observations

Sample

1
2
3
4
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