Statistical Control

13. Which of the following characteristics makes it EASIER to measure the quality of a service, relative to that of a product or facilitating good?

Quality Associates, Inc., a consulting firm, advises its clients about sampling and statistical procedures that can be used to control their manufacturing processes. IN one particular application, a client game quality associates a sample of 800 observations taken during a time in which that client's process was operating satisfactorily. The sample standard deviation for there data was .21 ; hence, with so much data, the population standard deviation was assumed to be .21. Quality associates then suggested that random samples of size 30 be taken periodically to monitor the process on an ongoing basis. BY analyzing the new samples, the client could quickly learn whether the process was operating satisfactorily. when the process was not

A process that monitors standards by take measurements and corrective action as needed. It is in control when only variation is natural, if variation is assignable then discover cause eliminate it. Take samples to inspect/ measure- reduce inspection time, reduce opportunity of bad quality. Control charts graph of process data over time-show natural and assignable causes. Control charts for variable data (characteristic that is measured, length,height, etc) are X-chart (average) and R-chart (range)must use x and r to get correct results. central limit theorem follow normal curve. When we know . When we don’t know . Control charts for attributes (categorical-defective, good/bad) P-chart (percent) or C-chart

The volume of chemicals (in mL) is the controlled variable of the experiment. As it will be the same in each trial and will not be changed, it is considered the controlled variable. Another controlled variable is the equipment that is used. For each trial the same equipment is always used, and therefore is also a controlled variable. The type of chemicals themselves are also controlled as for each trial they are the only chemicals used.

This type of chart is used when one wants to identify the total number of defects that have occurred during a sampling period. The number of samples that occur during the period are essentially the same. This chart has the number of defects on the vertical axis and the number of samples (weeks) on the horizontal axis. The sample size for this problem is over a period of 20 weeks, where a new process was implemented at week 11. Since a new plan was implemented, it caused the two different graphs to appear. The first graph, which occurs before week 11, has a UCL of 28.4 and an average of 16.3. A UCL stands for an upper control limit, which is generally 3 standard errors from the median, and is always the top line of the graph. The median is used as the centerline of the graph. An LCL is apparent in the graph (bottom line), but no exact value is given. The points that are shown on the graph are the “statistical measurement samples taken from the process at different times” (Control Charts PPT., 25, 2016). The second graph, which occurs after week 11, has a UCL of 7.4 and an average of 2.6. This subgroup is also complete with an upper UCL line and a median centerline. After week 11, a new plan was implemented into the hospital to reduce the number of defects. The plan that they used decreased the total number of defects, decreased the UCL, average, and LCL. A strategy that may have been able to reduce the amount of defects was Six Sigma. Six Sigma would work for this type of scenario because it measures how many defects exist in a process and you can figure out how to eliminate them all

Spartan Plastic LimitedCase StudyProblem Statement:Spartan Plastics Canada Limited is a subsidiary of Spartan International U.S.A. Spartan manufactured extruded plastic parts. Mr. David Angove was the vice-president of the company. It is a small company with only 50 employees, the company manufacturing process is complex, since the company had been improved the manufacturing process from the original to modified, there are still many problems appearing in the company.

Quality Associates, Inc. is a consulting firm that advises its clients about sampling and statistical procedures that can be used to control manufacturing processes. In one case, a client provided Quality Associates with a sample of 800 observations that were taken during a time when the client's process was operating satisfactorily. The sample standard deviation for these data was .21, hence, the population standard deviation was assumed to be .21. Quality Associates then suggested that random samples of size 30 be taken periodically to monitor the process on an ongoing basis. By analyzing the new samples, the client could quickly learn whether the process was operating satisfactorily. When the process was not operating

Quality Associates, Inc., a consulting firm advises its clients about sampling and statistical procedures that can be used to control their manufacturing processes. In one particular application a client gave Quality Associates a sample of 800 observations taken during a time in which the client’s process was operating satisfactorily. The sample standard deviation of this data was 0.21; hence with so much data, the population standard deviation was assumed to be 0.21. Quality Associates then suggested that random samples of size 30 be taken periodically to monitor the process on an ongoing basis. By analyzing the new samples, the client could quickly learn whether the process was operating satisfactorily. When the process was not operating satisfactorily, corrective action could be taken to eliminate the problem. The design specification indicated the mean for the process should be 12. The hypothesis test suggested by Quality Associates follows.

5.  Assuming that operators will continue to take samples of 10 sheets each hour to check if the process is in control, what control limits should Douglas set for the case when extrusion is a Six Sigma process?

Issue: Dynamic Seal, a precision parts manufacturer with a reputation for high quality, does not currently utilize a Statistical Process Control (SPC) system. However, United Airlines (UA), a major customer representing 14% of Dynamic Seal’s business, insists they implement an SPC system or loose United Airlines’ business. In addition Dynamic Seal do not have a sound preventative measure quality control system in place, preferring 100% inspection to cull bad quality, rather than building parts correctly from inception.

with the start of the Iraq War, many companies are trying to find better and cheaper ways to

* Introduces the construction and use of statistical process control (SPC) charts and an understanding of the relationship between SPC and conformance quality.

We present an overview of literature on nonparametric or distribution-free control charts for uni-variate variable data. We highlight various advantages of these charts while pointing out some of the disadvantages of the more traditional, distribution based control charts. Specific observations are made in the course of review of articles and constructive criticism is offered so that opportunities for further research can be identified. Connections to some areas of active research are made, such as sequential analysis, which are relevant to process control. We hope that this article leads to a wider acceptance of distribution- free control charts among practitioners and serves as an impetus to future research and development in this area.

• Objective of quality control is to develop a scheme for sampling a process, making a quality measurement of interest on sample items, and then making a decision as to whether

In a nutshell, this application helps a common smartphone user with no major background in statistics and no access to costly mathematical software to generate control charts anywhere anytime and save results in .png format, pdf format.