A quality engineer collected process data for 10 subgroups with each subgroup consisting of three samples (n=3). The averages and ranges of samples in each subgroup are summarized in Table 1 below. Table 1. Subgroup Data (1-1) Calculate center line X of X chart. (1-2) Calculate average range R, which is also the rontar lino nf D chnot (1-3) Calculate upper control limit (UCL) and lower control limit (LCL) of X chart by approximation using