Is it possible for a range chart to be stable? When the corresponding next bar chart is unstable. No$,$ these charts are set. They are both either stable or unstable, but never one of each, no$.$ The x bar chart is calculated from range chart. At this stable, the x bar chart must be stable to$.$ Yes, each chart measures a different aspect of the process variation so the short$-$term variation can be stable. Range chart while the process average is unstable. X bar chart yes, they are calculated indentedly of$.$ Each other so these charts do not affect each other