Hi,

I just want to ask if my answers are correct in getting **trial central line** and **control limits**. Subgroup size is 4. Subgroup number is 25.

The given are:

∑ (X-bar) = 12063

∑R= 626

X-double bar= 482.52

R-bar= 25.04

A_{2 = 0.729 }

D_{4} = 2.282

D_{3} = 0

UCLx̄= (X-double bar)+A

2 (R-Bar)

= 482.52+ 0.729(25.04)

= 500.77

LCLx̄= (X-double bar)-A

2 (R-Bar)

= 482.52- 0.729(25.04)

= 464.27

_{
UCL (R-bar)= D4(R-bar) }

= 2.282(25.04)

= 57.14

LCL (R-bar)= D_{3}(R-bar)

= 0(25.96)

=0

Did I use the correct formulas?

Thanks I hope you can helpme.