UCLR $=$ D$4$R UCLx $=$x $+$ A$2$R

LCLR $=$ D$3$R LCLx $=$x $-$ A$2$R

Factors for R Charts

Number of Observations

in Subgroup, n

Factor for

x$-$bar Chart A$2$

Lower Control Limit

D$3$

Upper Control Limit

D$4$

$21\mathrm{.}8803\mathrm{.}27$

$31\mathrm{.}0202\mathrm{.}57$

$40\mathrm{.}7302\mathrm{.}28$

$50\mathrm{.}5802\mathrm{.}11$

$60\mathrm{.}4802\mathrm{.}00$

$70\mathrm{.}420\mathrm{.}081\mathrm{.}92$

$80\mathrm{.}370\mathrm{.}141\mathrm{.}86$

$90\mathrm{.}340\mathrm{.}181\mathrm{.}82$

$100\mathrm{.}310\mathrm{.}221\mathrm{.}78$