Q4

Computer upgrade times (in minutes) are being evaluated. Samples of five (5) observations each have been taken, and the results are listed in the table below.

SAMPLES 1 / 2 / 3 / 4 / 5 / 6

79.2 / 80.5 / 79.6 / 78.9 / 80.5 / 79.7

78.8 / 78.7 / 79.6 / 79.4 / 79.6 / 80.6

80.0 / 81.0 / 80.4 / 79.7 / 80.4 / 80.5

78.4 / 80.4 / 80.3 / 79.4 / 80.8 / 80.0

81.0 / 80.1 / 80.8 / 80.6 / 78.8 / 81.1

a) Determine UCL and LCL for mean and range charts.

b) Is this process in control?