Adetergent company periodically tests its products for variations in the fill weight. to do this, the company uses -charts. eight samples, each containing six detergent boxes, were selected from different batches. historical data for fill weight (in ounces) of the eight samples is presented below. sample sample mean sample range 1 15.80 0.42 2 16.10 0.38 3 16.02 0.08 4 15.95 0.15 5 16.12 0.42 6 16.18 0.23 7 15.87 0.36 8 16.20 0.40 if a2> for the -chart is 0.483, the upper control limit for the -chart (ucl ) will be:

a. more than 18.
b. more than 16 but less than or equal to 18.
c. less than or equal to 14.
d. more than 14 but less than or equal to 16.