
Statistical Quality Control
747
Chapter 17
PB
FORMULAS
Chart:
Control limit considering range:
Control limit (CL) = x
Upper control limit (UCL) =
R+
2
Lower control limit (LCL) =
R−
2
Control limit considering standard deviation:
Control limit (CL) = x
Upper control limit (UCL) =
s+
3
Lower control limit (LCL) =
s−
3
R Chart:
Control limit (CL) =
Upper control limit (UCL) =
3
Lower control limit (LCL) =
4
p Chart:
Control limit (CL) =
Upper control limit (UCL) = p
p
3
Lower control limit (LCL) = p
p
3
c Chart:
Centreline (CL) =
Upper control limit (UCL) =
+ 3
Lower control limit (LCL) =
− 3
np Chart: ...