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Question 1

A sticky scale brings Webster’s attention to whether caulking tubes are being properly capped. If a significant proportion of the tubes aren’t being sealed, Webster is placing their customers in a messy situation. Tubes are packaged in large boxes of 144. Several boxes are inspected and the following number of leaking tubes are found:

Sample Tubes Sample Tubes Sample Tubes

1 3 8 6 15 5

2 5 9 4 16 0

3 3 10 9 17 2

4 4 11 2 18 6

5 2 12 6 19 2

6 4 13 5 20 1

7 2 14 1 Total 72

Calculate p-chart three-sigma control limits to assess whether the capping process is in statistical control.

Solution

n = 144, EMBED Equation.2

EMBED Equation.2

EMBED Equation.2 . Therefore, statistical control.

Question 2

Webster Chemical’s nominal weight for filling tubes of caulk is 8.00 ounces EMBED Equation.2 0.60 ounces. The target process capability ratio is 1.33. The current distribution of the filling process is centered on 8.054 ounces with a standard deviation of 0.192 ounces. Compute the process capability index to assess whether the filling process is capable and set properly.

Answer:

Process capability ratio:

EMBED Equation.2

Process capability index:

EMBED Equation.2

EMBED Equation.2