Median control
charts are not generally recommended,
but save calculation as long as the subgroup
size is an odd number:
Upper
Control Limit 

Lower
Control Limit 
: 
Where the factors are:
n 
2 
3 
4 
5 
6 

1.88 
1.19 
0.80 
0.69 
0.55 
It is not usual to use range charts with
median charts, because it defeats the purpose
of simple calculation. All the data values
from the subgroup may be plotted on the
chart to indicate the spread:
