.A process for filling liquid laundry detergent bottles monitors the volume in each bottle.The operations manager has taken 5 samples with 4 observations (bottles) in each sample to determine if the variation in volume (filling amount in a bottle) is under control. The measurement unit is fluid ounces (keep two decimal places).

Bottle	Sample 1	Sample 2	Sample 3	Sample 4	Sample 5
1	11.8	12.0	11.8	11.9	10.7
2	12.1	12.0	11.8	12.0	11.2
3	12.0	11.9	11.9	11.8	11.9
4	12.2	11.8	11.7	11.9	11.7
Mean	12.0	11.9	11.8	11.9	11.4
Range	0.4	0.2	0.2	0.2	1.2

(a) Do you use the variable control charts or the attribute control chart? Why?

(b) Construct the control charts you determined in Part (a) to see if the filling process is under control.