Exam 16: Quality Control and Spc

The center line (p-bar) for a p-chart is 0.50 with an UCL = 0.70 and a LCL = 0.35. The results of the next eight sample means are 0.45, 0.60, 0.39, 0.44, 0.48, 0.53, 0.54, and 0.61. What would you do?

A c-chart is used to monitor the fraction nonconforming, whereas a p-chart monitors the number of nonconformances per unit.

Common cause variation

Define Statistical Process Control (SPC) and differentiate between common cause and special (or assignable) cause variation.

Over-adjusting a process that is in control will usually increase the variation in the output.

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

Jim is a quality control manager at a clothing manufacturer. He is studying a quality problem where zippers are purchased from an outside supplier and have been discovered to be poorly constructed. When the zipper is manufactured correctly, it should have a mean length of 15 inches and a range of .5 inches. Jamie proposes that 25 samples of five observations each should be collected on a daily basis. He plans to prepare control charts to monitor the progress of the supplier's quality performance on the zippers. a.What are the upper and lower control limits and center line for an R-chart? b.What are the upper and lower control limits and center line for an x-bar chart?

With good management, all variability of output from any goods- or service-producing process can be eliminated.

Honda wants to monitor the number of blemishes (scratches, blisters, etc.) on the fenders of its cars using a statistical process control chart. The most appropriate type of SPC chart is

Over several days, 25 samples of 100 items each were tested for electrical resistance. A total of 60 items failed. Determine and the control limits for a p-chart.

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?

In-process quality control is typically performed by the employees who run the processes.

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?

Evaluating the trade-offs between the costs of detecting and replacing a defective part or allowing it to continue on through the production process is related to

A key element of a control system is the ability to measure performance and compare it to a performance standard.

The goal of statistical process control (SPC) is to help identify and eliminate unwanted causes of variation.

An operator has determined what her percent defectives is for the machine which she operates. Based on several samples of 75 observations, she found p-bar to be 10%. She wants to set up a control chart using 3 standard deviation control limits. a.What is the upper control limit for a p-chart? b.What is the lower control limit for a p-chart?

Which of the following is not a component of a control system?

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

Quality control of front-office operations in services can effectively use many of the same techniques that are applied in manufacturing.