Answer:
upper control limit = 6.058
lower control limit = 0.442
Step-by-step explanation:
Given that:
The numbers of sample n Mogul executives took = 8 Eagletrons at a time.
They find out that the average sample mean is 88.50 mph and;
the average range [tex]\overline r[/tex] is 3.25 mph.
From the tables:
[tex]\text {Table values for n = 8 } \left \{ {{D_4=1.864} \atop {D_3=0.136}} \right.[/tex]
Control Limit = [tex]\overline r[/tex] = 3.25
Therefore; the upper control limit and the lower control limit can be computed as follows:
upper control limit = [tex]D_4 \overline r[/tex]
upper control limit = 1.864(3.25)
upper control limit = 6.058
lower control limit = [tex]D_3 \overline r[/tex]
lower control limit = 0.136(3.25)
lower control limit = 0.442