# Question: Consider all 30 observations on the first two process variables

Consider all 30 observations on the first two process variables in Table 11.6. Calculate an estimate of the sample covariance matrix using both estimators S1 and S2 discussed in Section 11.3.2. Are the estimates very different? Discuss your findings.

## Relevant Questions

Suppose that there are p = 4 quality characteristics, and in correlation form all four variables have variance unity and all pairwise correlation coefficients are 0.75. The in-control value of the process mean vector is ...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 ...Rework Exercise 11.5, assuming that the subgroup size is n = 5. m = 30 preliminary samples, n = 5 sample size, p = 6 characteristics, = 0.005 (a) Find the phase II control limits assuming that = 0.005. (b) Compare ...Consider the data in Table 12.1. Suppose that an adjustment is made to the output variable after every observation. Compare the performance of this chart to the one in Table 12.1 and Figure 12.12. An article in Industrial and Engineering Chemistry (“More on Planning Experiments to Increase Research Efficiency,” 1970, pp. 60–65) uses a 25−2 design to investigate the effect of A = condensation temperature, B = ...Post your question