Exam 16: Quality Control and Spc

In developing process control charts, if special causes are present, they are not representative of true state of statistical control, and the calculations of the center line and control limits will be biased.

What is the purpose of a process-capability study and what is a process capability index?

A high-paced discount store in Los Angeles has noticed that checking errors have increased recently.They plan to use control charts with three standard deviation control limits to monitor the process.They decided to take a sample of 100 transactions over each of 10 days.The number of transactions in error for each day was 5, 7, 6, 5, 6, 4, 6, 3, 10, and 8. a.What is the center line for the p chart? b.What is the upper control limit for the p chart? c.What is the lower control limit for the p chart?

Quality control focuses on the design of a good or service to ensure meeting customer expectations.

A bottling machine fills soft drink bottles with an average of 12.000 ounces with a standard deviation of 0.002 ounces.Determine the process capability index, C_p, if the design specification for the fill weight of the bottles is 12.000 ounces plus or minus 0.015 ounces.

A manufacturer inspected 40 circuit boards and found a total of 640 defects.If the company wants to use SPC to control the manufacturing process by monitoring the number of defects per circuit board, what type of chart should they use and what should the control limits be?

The time to check out guests at a hotel was measured over the course of several weeks.Management believes that the target time for checking out guests should be between 2 and 4 minutes with a target of 3 minutes.The data gathered had a mean time of 2.75 minutes with a standard deviation of 0.4 minutes.Find and interpret C_p, C_pl, C_pu, and C_pk in the context of this situation.

A manufacturing company has a production process that has a target percent nonconforming of 4% which was developed based on numerous samples of 200 observations each.They want to develop control charts using 3 standard deviation limits. a.What is the center line for the p chart? b.What is the upper control limit for a p chart? c.What is the lower control limit for a p chart?

An airline found that on average, 0.62% of the luggage they received from passengers at LAX (Los Angeles Airport) is lost or damaged.On a typical day, 1000 pieces of luggage pass through this airport.The upper control limits for a p chart for monitoring the daily fraction nonconforming?

Ritz-Carlton Hotel Company uses which one of the following methods to control quality?

Explain the issues associated with selecting the appropriate sample size and sampling frequency for control charts.

Common cause variation

Common cause variation is

Which of the following suggests a process that is not in control?

Both the p-chart and the c-chart use variable data.

Which of the following is most closely related to Statistical Process Control (SPC)?

Define "quality at the source."

"Quality at the source" focuses on supplier quality at the beginning of a value chain.

The upper and lower specification limits for a component are 4.20, and 4.30 ounces, respectively.The process standard deviation is .02, and the process average is 4.24 ounces.Which one of the following statements is true.

A supplier is producing a machined part for the transmission of your vehicle.The upper specification limit is 0.125 cm and the lower specification limit is 0.085.The process standard deviation for the process that makes this part is 0.008 and the process average is 0.105.What conclusion can be drawn from these process capability data?