Exam 3: Statistical Process Control

Variable control charts are used to monitor measurable characteristics of a process's outputs rather than descriptive characteristics.

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 UCL for an R-chart of this process would be

Tolerances reflect the amount of common cause variation allowed in a process.

Statistical process control is only effective for service processes.

When a control chart detects no special cause (nonrandom) variation in a process, the upper and lower control limits are the same value.

Marble Inc. makes countertops from a variety of high-end materials. To monitor the quality of its production processes the company randomly selects one countertop and counts the number of blemishes. The results for ten samples are shown below: 5. 6. Given the sample information above, the UCL using sigma = 3 for this process would be

A company manufactures a product that has a design (nominal) target width of 5 inches with tolerances of + .05 inch. The process that produces the product has a mean of 4.995 inches and a standard deviation of 0.01 inch. The process capability ratio for this process is

For a given process, the process capability ratio is NOT not related to its control specification limits.

Statistical process control is a tool used to monitor and improve quality.

A variable measure is a product characteristic such as

After special cause variation is detected, the focus changes to identifying the root cause of the variation and eliminating it.

When constructing a control chart for the first time, all points should be within the control limits indicating the process is in control.

Consider a production process that produces batteries. A quality engineer has taken 20 samples each containing 100 batterieslight bulbs. The total number of defective batteriesunits observed over the 20 samples is 1200. The LCL for the control chat constructed using two sigma is

Consider a production process that produces tires. A quality engineer has taken 15 samples, each containing 200 tires. The total number of defective tires over the 15 samples is 340. The centerline for the control chart is

The process centerline for both xbar and R charts are both the same value because they are based on the same raw data.

An attribute measure is a product characteristic such

The formulas for determining the upper and lower control limits are based on the number of standard deviations, z, from the process average. Management usually selects a z value of _______because it wants a high probability that these sample values will fall within the control limits.

Which of the following could be responsible for variability that is special cause (nonrandom)?

Process control charts are often used at a critical point after which it is difficult to correct or rework the process output.

Only certified statisticians should use Excel to construct a control chart for a process.