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The p-chart models "pass"/"fail"-type inspection only, while the c-chart (and u-chart) give the ability to distinguish between (for example) 2 items which fail inspection because of one fault each and the same two items failing inspection with 5 faults each; in the former case, the p-chart will show two non-conformant items, while the c-chart ...
Control charts are graphical plots used in production control to determine whether quality and manufacturing processes are being controlled under stable conditions. (ISO 7870-1) [1] The hourly status is arranged on the graph, and the occurrence of abnormalities is judged based on the presence of data that differs from the conventional trend or deviates from the control limit line.
A radar chart or "spider chart" or "doi" is a two-dimensional chart of three or more quantitative variables represented on axes starting from the same point. A waterfall chart also known as a "Walk" chart, is a special type of floating-column chart. A tree map where the areas of the rectangles correspond to values. Other dimensions can be ...
Control charts attempt to differentiate "assignable" ("special") sources of variation from "common" sources. "Common" sources, because they are an expected part of the process, are of much less concern to the manufacturer than "assignable" sources. Using control charts is a continuous activity, ongoing over time.
The control limits for this chart type are ¯ ¯ where ¯ is the estimate of the long-term process mean established during control-chart setup. The observations u i = x i n i {\displaystyle u_{i}={\frac {x_{i}}{n_{i}}}} are plotted against these control limits, where x i is the number of nonconformities for the ith subgroup and n i is the ...
In statistical quality control, the p-chart is a type of control chart used to monitor the proportion of nonconforming units in a sample, where the sample proportion nonconforming is defined as the ratio of the number of nonconforming units to the sample size, n.
In statistical quality control, the individual/moving-range chart is a type of control chart used to monitor variables data from a business or industrial process for which it is impractical to use rational subgroups. [1] The chart is necessary in the following situations: [2]: 231
In statistical process control (SPC), the ¯ and R chart is a type of scheme, popularly known as control chart, used to monitor the mean and range of a normally distributed variables simultaneously, when samples are collected at regular intervals from a business or industrial process. [1]