
Chapter 17
712
R
R
i
k
=
=
∑
1
The average sample standard deviation for all the samples can also be determined. This is
denoted by
s
s
i
k
=
=
∑
1
6. On the basis of the sample size, the value of A
2
(when using range) or the value of A
3
(when
using standard deviation) must be determined. These values can be determined from the
factors for control charts given in the appendices.
7. Determine the control limit (CL), the upper control limit (UCL), and the lower control
limit (LCL) by using the following formula:
Control limit considering range
Control limit (CL) =
x
Upper control limit (UCL) =
R+
2
Lower control limit (LCL) =
R−
2
Control limit ...