Introduction to Probability and Statistics for Engineers and Scientists

556 Chapter 13:Quality Control

SinceX= 35.94,S=4.35,c(5)=.9400, we see from Equations 13.2.4 and 13.3.4 that
the preliminary upper and lower control limits forXandSare

UCL(X)=42.149

LCL(X)=29.731

UCL(S)=9.087

LCL(S)=−.386

0 5

UCL

10 15 20 25

LCL

10

8

6

4

2

0

− 2

Control chart for S

Subgroup

(a)

0 5

UCL

10 15 20 25

LCL

45

40

35

30

25

Control chart for X

Subgroup

(b)

FIGURE 13.2