Table 15-1
-Refer to Table 15-1.The average range of a process for packaging cereal is 1.1 ounces.If the sample size is 10,find the lower control chart limit for the range chart.
A)0.245
B)1.955
C)1.777
D)0.223
E)None of the above

Question

Table 15-1 
-Refer to Table 15-1.The average range of a process for packaging cereal is 1.1 ounces.If the sample size is 10,find the lower control chart limit for the range chart.
A)0.245 
B)1.955 
C)1.777 
D)0.223 
E)None of the above

Quizplus · Accepted Answer

The lower control chart limit for the range chart is given by:LCL = D3 * σ / √nwhere:D3 is the lower control limit factor for a sample size of 10σ is the standard deviation of the processn is the sample sizeFrom Table 15-1, we find that D3 = 0.223. The standard deviation of the process is not given, but we can estimate it using the average range:σ = R / d2where:R is the average ranged2 is a constant that depends on the sample sizeFrom Table 15-1, we find that d2 = 2.326 for a sample size of 10. Therefore,σ = 1.1 / 2.326 = 0.473Substituting these values into the formula for the LCL, we get:LCL = 0.223 * 0.473 / √10 = 0.245Therefore, the lower control chart limit for the range chart is 0.245.

Table 15-1 -Refer to Table 15-1.The Average Range of a Process for a Process