Pizazz manufactures a 5.0 oz.energy drink of the same name.Because the cans are so small,consumers are concerned that they are not receiving the full 5 ounces in each can.A quality engineer at the company is charged with analyzing the filling process and ensuring accurate readings.On 15 different occasions over the past month,she has taken a sample of 6 energy drinks off the production line and recorded their weight.If the sum of the sample means is 80.20 ounces and the sum of the sample ranges is 12.68 ounces,the LCL for an X-bar chart of this process would be
A)4.50
B)4.65
C)4.79
D)4.94

Question

Quizplus · Accepted Answer

To find the LCL for an X-bar chart, we need to use the formula:

LCL = X-bar - A2(R-bar)

where

X-bar = sum of sample means / number of samples = 80.20 / 15 = 5.3467 ,
R-bar = sum of sample ranges / number of samples = 12.68 / 15 = 0.8453 ,
A2 = control chart constant (for n=6) = 0.577 .

Therefore,

LCL = 5.3467 - 0.577(0.8453) = 4.9436 ≈ 4.94 .

The closest answer choice to 4.94 is D, so the best choice is:

Answer: D

Pizazz Manufactures a 5