Statistical Process Control Problems:

1. The Canine Gourmet Company produces delicious dog treats for canines with discriminating tastes. Management wants the box-filling line be set so that the average weight per box is 43.5 grams. When the process is in control, the range in the weight of each sample has averaged 10 grams. (Therefore, X-double bar = 43.5 grams and R-bar = 10 grams.). To make sure the process is in control, an inspector at he end of the filling line periodically selects a random sample of 8 boxes and weighs each box (i.e., Sample Size = 8).

Question 1

1. Draw an X-bar chart for this process.

Question 2

1. Draw an R-chart for this process.

1. The results of the last five samples (of eight boxes) are as follows. Is the process in control or out of control ? Plot these points on the chart drawn in part a to arrive at your answer.

SampleX-bar

1 44

2 40

3 46

4 39

5 48

1. The Marlin Company produces plastic bottles to customer order. The process that produces a shampoo bottle has been set up for large scale production. To determine if the process is in control, the diameter of the neck of the bottle is measured. Twenty-five samples of six bottles each were taken to construct the process control chart. For these samples, X-double bar = 0.60 inches and R-bar = 0.12 inches. Given this information:

question

1. Draw an X-bar chart for this process.

1. Draw an R-chart for this process.

1. The results of five recently taken samples (of six bottles) are as follows. Is the process in control or out of control ? Plot these points on the chart drawn in part a to arrive at your answer.

Sample X-bar

1 0.565

2 0.635

3 0.580

4 0.615

5 0.570