Sample range chart - control charts for variables, Operation Management

Sample Range Chart - Control Charts for Variables

Whilst the sample mean chart provides control over the process setting, it provides no protection from change (increase) in the standard deviation of the process output. The second control chart (shown here) provides this by means of control limits set out from the average sample range (¯R) , determined when the process was stable.

663_sample range chart 1.png

Again, the control limits are established as 1-in-40 warning and 1-in-1000 action limits. They are determined by multiplying the average sample range (¯R) by the appropriate D' coefficient from the table below.

Upper action limit = D'0.9999 ¯R

Upper warning limit = D'0.975 ¯R

Lower warning limit = D'0.025 ¯R

Lower action limit = D'0.001 ¯R

1434_sample range chart.png

In practice, the lower control limits are often omitted, the reasoning being that exceptionally low range values represent welcome consistency. However, such low-probability results are unlikely to be produced by a stable process, and may, in fact, be an indication that the measurements are incorrect.

Posted Date: 3/15/2013 6:05:46 AM | Location : United States

Related Discussions:- Sample range chart - control charts for variables, Assignment Help, Ask Question on Sample range chart - control charts for variables, Get Answer, Expert's Help, Sample range chart - control charts for variables Discussions

Write discussion on Sample range chart - control charts for variables
Your posts are moderated
Related Questions
Which of the following in not an advantage of skimming pricing? A. It allows a manufacturer to quickly recover its research and development costs. B. It permits marketers to contro

How will you influence people to strive willingly for group objectives in our organization (target baes industry)?Apply your interpersonal influence through communication process t

Imagine this is the only position of its kind in the organization. From this perspective, design a performance appraisal program to assess your job performance.

Q3. Solve the following Linear Programming Problem using Simple method. Maximize Z= 3x1 + 2X2 Subject to the constraints: X1+ X2 4 X1+ X2 2 X1, X2 0

1. Analyze the basic technology underlying health care information systems and determine the most pressing need for innovation. 2. Explain (with specific examples using local hospi

Lysosomes Lysosomes were first discovered by Christian de Duve. Unlike other organelles which were detected by microscbpe, these were first discovered biochemically. Later, ele

In the context of International business, what is meant by the term Cpolitical risk? In general, how do MNCs analyze this risk?

How can supervisors avoid receiving "canned" or rote

In excel how many cells should be used to represent each constraint?

Agents and employees of Apples Corporation and Oranges Corporation are convicted of conspiring to violate a federal law that is punishable by a term of imprisonment and a fine. Can