New highlights added 2024-03-25
Whenever you are asked to collect some data the problems of what to measure, how to measure, and when to measure all raise their heads. An operational definition puts written and documented meaning into a concept so that it can be communicated and understood by everyone involved (View Highlight)
How can you interpret the current value when the previous values are so variable? The key to understand ing any time series is to make a distinction between two types of variation. The first type of variation is routine variation. It is always present. It is unavoidable. It is inherent in the process. Because this type of variation is routine, it is also predictable. The second type of variation is exceptional variation. It is not always present. It is not routine. It comes and it goes. Because this type of variation is exceptional, it will be unpredictable. (View Highlight)
New highlights added 2024-04-23
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Bar charts and running records provide pictures of your data. In each case you obtain a pic ture that displays relationships or data in their context. In many cases these contextual dis plays will be sufficient (View Highlight)
New highlights added 2024-04-24
l (View Highlight)
New highlights added 2024-04-28
w many values were used to compute the range. To see why this is the case consider what wo (View Highlight)
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New highlights added 2024-05-04
When a process displays predictable variation, that variation may be thought of as the result of many different cause-and-effect relationships where no one cause is dominant over the others. While every process is subject to many different cause-and-effect relationships, predictable processes are those in which the net effect of the multiple causes is a sort of static equilibrium. Deming’s terminology for this condition was common cause variation (View Highlight)
If a process displays predictable variation, then the variation is the result of many common causes and it will be a waste of time to look for assignable causes. Improvement will only come by changing a major portion of the process. (View Highlight)
New highlights added 2024-05-04
Moving Range Chart is a simple way to signal to others that you do know the correct way of computing the limits. Since there are many who do not know the difference between the right and wrong ways of computing limits for individual values, and since the right ways all depend upon the moving ranges, the use of an mR Chart will differentiate you from the uninformed. (View Highlight)
New highlights added 2024-05-04
The “Has a Change Occurred?” Chart (View Highlight)
9.1 Comparing Groups Using Process Behavior Charts 9.2 The “Has a Change Occurred?” Chart (View Highlight)
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So do not attempt to use any do-it-yourself formulas. Use the formulas and the scaling factors shown in the next section, and if a stranger, or even a friend, offers you another way of computing limits, just say no! (View Highlight)
New highlights added 2024-05-10
n (View Highlight)