A factory supervisor is concerned that the time it takes workers to figure out an important production task (measured in seconds) is too 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 below.

_

Hour X R

1 18.4 25

2 16.9 27

3 23.0 30

4 21.2 23

5 21.0 24

6 24.0 25

7 19.3 12

8 15.8 14

9 20.0 13

10 23.0 11

It is also decided that lower and upper specification limit for the critical-to-quality variable should be 10 and 30 seconds.

suppose the supervisor constructs anRchart to see if the variability in collection times is in-control. ThisRchart is characterized by ??

Decreasing trend

Increasing trend

In-control

Individual outliers

suppose the sample mean and range data were based on 6 observations per hour instead of 5. How would this change affect the lower and upper control limits of an R chart?

LCL would increase; UCL would decrease.

LCL would remain the same; UCL would decrease.

Both LCL and UCL would remain the same.

LCL would decrease; UCL would increase.

Thank you for any help on these questions.