Assume that you are doing production support and one day your development server crashes, this is not normal process , like it does not happen daily, hence its a special cause.
Another example, say due to human error you deleted all records in a table, its a special cause.
In manufacturing, if there is one item which is way outside measurement threshold, then its considered special cause. Normal cause or common cause will be measurements insdie the pre-determined thresholds
Common causes (random causes) are normal process variations. Special causes are unusual events. A process goes out of control when there are special causes of variation.
A control chart is a statistical tool used to distinguish between variation in a process resulting from common causes and variation resulting from special causes. Some variation may be the result of causes which are not normally present in the process. This could be special cause of variation. Some variation is simply the result of numerous, ever-present differences in the process. This is a common cause variation. Control charts differentiate between these two types of variation. It presents a graphic display of process stability or instability over time. Process stability is defined as a state in which a process has displayed a certain degree of consistency in the past and is expected to continue to do so in the future
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Mon, 04/22/2013 - 02:11
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Assume that you are doing
Assume that you are doing production support and one day your development server crashes, this is not normal process , like it does not happen daily, hence its a special cause.
Another example, say due to human error you deleted all records in a table, its a special cause.
In manufacturing, if there is one item which is way outside measurement threshold, then its considered special cause. Normal cause or common cause will be measurements insdie the pre-determined thresholds
Common causes (random causes) are normal process variations. Special causes are unusual events. A process goes out of control when there are special causes of variation.
A control chart is a statistical tool used to distinguish between variation in a process resulting from common causes and variation resulting from special causes. Some variation may be the result of causes which are not normally present in the process. This could be special cause of variation. Some variation is simply the result of numerous, ever-present differences in the process. This is a common cause variation. Control charts differentiate between these two types of variation. It presents a graphic display of process stability or instability over time. Process stability is defined as a state in which a process has displayed a certain degree of consistency in the past and is expected to continue to do so in the future