A factory supervisor is concerned that the time it takes wor

A factory supervisor is concerned that the time it takes workers to complete an important production task (measured in seconds) is to erratic and adversely affects expected profits. The supervisor proceeds by randomly sampling 5 individuals per hour for a period of 10 hours. The sample mean and range for each hour are listed below.

Day

18.4

16.9

21.2

19.3

15.8

1) Suppose the supervisor constructs an R chart to see if the variability in production times is in-control. What is the center line of this R chart?

a) 20

b) 20.56

c) 20.40

d) 24

2) Suppose the supervisor constructs an R chart to see if the variability in production times is in-control. What are the lower and upper control limits of this R chart?

a) -2.33, 43.13

b) -2.28, 42.28

c) 0, 42.28

d) 0, 43.13

3) Suppose the supervisor constructs an R chart too see the variability in production times is in-control. The R chart is characterized by which of the following.

a) increasing trend

b) decreasing trend

c) in control

d) Individual outliers

4) suppose the analyst constructs an x chart to see if the production process is in control. What is the center line for this chart?

a) 20

b) 20.26

c) 21

d) 24.26

5) ) suppose the analyst constructs an x chart to see if the production process is in control. What are the lower and upper control limits for this chart?

a)10, 30

b) 8.49, 32.03

c) 5.39, 35.13

d) 4.96, 35.56

6) suppose the analyst constructs an x chart to see if the production process is in control. Which expression best describes this chart?

a) in control

b) increasing trend

c) decreasing trend

d) Individual outliers