A product has three quality characteristics. The nominal values of these quality characteristics and their sample covariance matrix have been determined from the analysis of 30 preliminary samples of size n = 10 as follows:

The sample means for each quality characteristic for 15 additional samples of size n= 10 are shown in Table 11E.2. Is the process in statistical control?

Construct a T2 control chart using these data. Use the phase II limits.

1.40 1.02 1.05 x=| 3.5 | S=11.02 1.35 0.98 1.05 0.98 1.20 3.0 2.8 TABLE 11E.2 Data for Exercise 112 Sample Number 2 X3 3.7 3.9 3.0 24 3.0 3.3 2.8 4.6 4.2 3.0 3.3 3.0 2.2 3.1 3.0 3.1 2.8 3.0 4.0 3.8 3.0 2.4 2.0 2.6 18 3.2 10 3.9 3.0 3.0 12 13 14 15 4.1 4.7 3.2 3.6 2.8