Why is the correlation between X1j and X2j equal to –0.17 for the independent case (“I”) i...

Why is the correlation between X_1j and X_2j equal to –0.17 for the independent case (“I”) in Table 11.3, since independent random variables are uncorrelated (see Prob. 4.8)?

TABLE 11.3 Statistical results of CRN for the M/M/1 queue vs. the M/M/2 queue