One changing sample moves both mean and range in a finite ledger. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.
highlighted = computed this step
The first row is a balanced four-sample ledger
With top sample eight, the average is five and the range is six.
Vˉ=5,R=6
Raising one sample moves both average and range
Changing only the top sample to twelve raises the average to six.
Vˉ=6,R=10
A larger spike keeps the count but widens the ledger
The third row shows why one outlier changes more than a caption.