|
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:
|
