Question

Calculate:

  UCLR ̅, LCLR ̅ given the following information:

	5 Samples consisting of 4 observations each (n)
	Sample 1 Values	Sample 2 Values	Sample 3 Values	Sample 4 Values	Sample 5 Values
1	10.20	10.30	9.70	9.90	9.80
2	9.90	9.80	9.90	10.30	10.20
3	9.80	9.90	9.90	10.10	10.30
4	10.10	10.40	10.10	10.50	9.70

Answer 1

I have used excel to calculate UCL and LCL for Rbar. I have provide both images one with calculations and otther with formula used.

for R bar chart you need constants D3 for LCL and D4 for UCL.

in our case sample size is 4 so D3=0 and D4=2.282

so LCL=D3*Rbar

UCL=D4*Rbar