Question

Sample Mean Range 16 8 12 13 6 6 4 15 10 10 11 10 16 13 14 0 14 17 11 12 IU 12 12 11 13 14 12 7 8 13 9 11 14 7 13 15 10 15 Subsequently, samples of size 5 were taken from the process every week for the next 10 weeks. The times were measured and the following results oblained: Sample Mean Range 16 9 17 12 13 18 7 8 19 13 6 20 15 14 21 17 16 22 11 13 23 20 12 24 18 10 25 16 8 9 Click the icon to view the table of factors for calculating three-sigma limits for the x-chart and R-chart. a. Construct the control charts for the mean and the range, using the original 15 samples. Set up the R-chart by specifying the center line and three-sigma control limits below. (Enter your responses rounded to two decimal places.) R-chart UCLR = 25.37 R = 12 LCL = 0 Set up the x-chart by specifying the center line and three-sigma control limits below. (Enter your responses rounded to two decimal places.) UCL X-chart = 0 LCL; = || Enter your answer in the edit fields and then click Check Answer.
Question pertains to the x-chart part

Answer 1

Answer a:

R= Max- Min	X-bar= average of sample
8	16
13	12
6	6
10	15
11	10
16	10
14	13
17	14
12	11
12	12
14	13
8	7
11	9
13	7
15	10
12.000	11.000
R-bar (Average of above values)	X-bar-bar (average of above values)

D4, D3 and A2 are taken from table of factors computing 3 sigma control limits, sample size=5

Range

D4 (n=5)=			2.115
D3 (n=5)=			0
control limits for Range,
CL or R-bar=			12.00
UCL=R-bar*D4			25.38
LCL=R-bar*D3			0.00

Xbar

A2 (n=5)			0.577
control limits for X bar,
CL or Xbarbar			11.00
UCL=Xbarbar+ (A2)*Rbar			17.92
LCL=Xbarbar- (A2)*Rbar			4.08