Control charts for attributes - statistical process control, Operation Management

Assignment Help:

Control Charts for Attributes - Statistical Process Control

Attribute data assume only two values, such as pass/fail or good/bad: they are counted rather than measured. Many quality characteristics can only be monitored in this way, such as the soundness of a soldered connection or the absence of components on a printed circuit board. Before proceeding further, a distinction must be made between defectives and defects. The term defective refers to a non-conforming item of output. A defect is a non-conforming feature of a single item of output: such an item may have more than one defect. Control charts for attributes have several advantages:

  • Collection of attribute data does not require measurement equipment and the skills to use them
  • They can be used to monitor any process, since the process output can be judged as either conforming or non conforming
  • Different attributes may be recorded on a single chart.

 

On the other hand, they have the following disadvantages:

  • Sample sizes are generally larger than for variables charts. Ideally, the sample size should be chosen such that, on average, at least one defective/defect is found in the sample
  • Attribute data do not indicate degrees of defectiveness: a non conforming item may be slightly defective or greatly defective.

 

Several attributes control charts have been devised, but those most commonly used are those described below. Two charts that look for defective items are discussed - the p-chart that looks at the proportion of defectives when the sample size is variable, and the np- chart that looks for the proportion of defectives in a constant sample size. Another sort of chart - the c-chart - is also described. This looks for the number of defects on an item.


Related Discussions:- Control charts for attributes - statistical process control

Determine a pareto analysis of the errors, 1. Construct and inerpret ...

1. Construct and inerpret a control chart for the packing slip data. 2. Construct a Pareto analysis of the errors. 3. What information might a separate char

Linear Programming Problem, A paper mill produces two grades of paper viz.,...

A paper mill produces two grades of paper viz., X and Y. Because of raw material restrictions, it cannot produce more than 400 tons of grade X paper and 300 tons of grade Y paper i

Explain factors weighing the pros and cons, Examine each possibility and th...

Examine each possibility and the factors you will consider in weighing the pros and cons.

Digitra; cell phone, Ask que Prepare Paul Jordan’s report to John Smithers ...

Ask que Prepare Paul Jordan’s report to John Smithers using regression analysis. Provide a summary of the cell phone industry outlook as part of Paul’s response. stion #Minimum 100

Explain the probable destiny of lee peterson''s company, Consider this: Lee...

Consider this: Lee Peterson has invented a new product that detects water leaks due to broken pipes and sends out an alarm similar to a smoke alarm. However, Lee has very little pe

Describe analyze the elements of a typical scope statement, Analyze the ele...

Analyze the elements of a typical scope statement and the significance of each element. As a project leader, determine how you would communicate the scope of a project to the proje

Linear trend equation, A cosmetics manufacturers marketing department has d...

A cosmetics manufacturers marketing department has developed a linear trend equation that can be used to predict annual sales of its popular Hand and Foot Cream. We are given F sub

Define the five-component model of an information system, Explain the five-...

Explain the five-component model of an information system. How can you use them?

Risks or opportunities of the strategies followed by pepsi, What are the ri...

What are the risks and opportunities of the strategies followed by Pepsi? of Coca Cola?

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd