The Last 25 Subgroups plot is located in the lower left corner of the Capability Sixpack - Normal.

The last 25 subgroups plot shows the distribution of the measurements in the last 25 subgroups. Note that the plotted points are the actual measurements.

This plot can tell you whether:

·    a subgroup contains any outliers

·    the data are symmetrically distributed around the process mean

·    the distribution changes across subgroups

For the piston data, the plotted points appear to be randomly and symmetrically distributed around the process mean.