Table 16-1
-Refer to Table 16-1. To guarantee that cans of soda are properly filled, some cans are sampled and the amounts measured. The overall average for the samples is 12 ounces. Each sample contains 10 cans. The average range is 0.4 ounces. The lower control chart limit for the sample averages would be
A) 12.1232.
B) 11.8768.
C) 13.2.
D) 12.308.
E) None of the above

Question

Table 16-1 
-Refer to Table 16-1. To guarantee that cans of soda are properly filled, some cans are sampled and the amounts measured. The overall average for the samples is 12 ounces. Each sample contains 10 cans. The average range is 0.4 ounces. The lower control chart limit for the sample averages would be
A) 12.1232. 
B) 11.8768. 
C) 13.2. 
D) 12.308. 
E) None of the above

Quizplus · Accepted Answer

The lower control chart limit for sample averages can be calculated as:
Lower limit = Overall average - (A2 x Average Range)
Where A2 is a constant for sample size 10 and can be found in statistical tables. For sample size 10 and a subgroup size of 2, A2 is 0.577.

Therefore, lower limit = 12 - (0.577 x 0.4) = 11.8768 ounces.

Choice B matches this result and is the correct answer.

Table 16-1 -Refer to Table 16-1. to Guarantee That Cans of Soda