. A product has three quality characteris-

tics. The nominal values of these quality characteristics and their sample covari-

ance matrix have been determined from the analysis of 30 preliminary samples of size n = 10 as follows:

3.0 1.40 1.02 1.05

₹= 3.5 S = 1.02 1,35 0.98 2.8 _1.05 0.98 1.20 The sample means for each quality char-

acteristic for 15 additional samples of size n = 10 are shown next. Is the process in statistical control?

Transcribed Image Text:

Saraple Number 3 123 1 3.1 3.7 3.0 2 3.3 3.9 3.1 2.6 3.0 2.4 2.8 3.0 2.5 5 3.0 3.3 2:8 6 4.0 4.6 3.5 7 3.8 4.2 3.0 8 3.0. 3.3 2.7 9 2.4 3.0 2.2 10 2.0 2.6 1.8 11 3.2 3.9 3.0 12 3.7 4.0 3.0 13 4.1 4.7 3.2 14 3.8 4.0 2.9 15 3.2 3.6 2.8