Finally, we analyze the relative biases when the process is off-center and data are selected from the Normal distribution. Weobserved that the values of RB based on the off-center process are similar, respectively, to the values of RB based on the cases where the process is centered and data are also selected from the Normal distribution. This issue indicates that the impact on the various estimators of Cpk and r is not relevant if we consider off-center processes.