Run chart


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Software Quality Management
Anna University Syllabus
About Run Chart

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Run chart

  1. 1. Run chart 1 Run chart A run chart, also known as a run-sequence plot is a graph that displays observed data in a time sequence. Often, the data displayed represent some aspect of the output or performance of a manufacturing or other business process. Overview Run sequence plots[1] are an easy way to graphically summarize an univariate data set. A common assumption of univariate data sets is that they behave like:[2] A simple run chart showing data collected over time. The median of the observed • random drawings; data (73) is also shown on the chart. • from a fixed distribution; • with a common location; and • with a common scale. With run sequence plots, shifts in location and scale are typically quite evident. Also, outliers can easily be detected. Examples could include measurements of the fill level of bottles filled at a bottling plant or the water temperature of a dishwashing machine each time it is run. Time is generally represented on the horizontal (x) axis and the property under observation on the vertical (y) axis. Often, some measure of central tendency (mean or median) of the data is indicated by a horizontal reference line. Run charts are analyzed to find anomalies in data that suggest shifts in a process over time or special factors that may be influencing the variability of a process. Run chart of eight random walks in one dimension starting at 0. The plot shows the current position on the line (vertical axis) versus the time steps (horizontal axis). Typical factors considered include unusually long "runs" of data points above or below the average line, the total number of such runs in the data set, and unusually long series of consecutive increases or decreases.[1] Run charts are similar in some regards to the control charts used in statistical process control, but do not show the control limits of the process. They are therefore simpler to produce, but do not allow for the full range of analytic techniques supported by control charts.
  2. 2. Run chart 2 References  This article incorporates public domain material from websites or documents [3] of the National Institute of Standards and Technology. [1] Chambers, John; William Cleveland, Beat Kleiner, nd Paul Tukey (1983). Graphical Methods for Data Analysis. Duxbury. ISBN 053498052X. [2] NIST/SEMATECH (2003). "Run-Sequence Plot" (http:/ / www. itl. nist. gov/ div898/ handbook/ eda/ section3/ runseqpl. htm) In: e-Handbook of Statistical Methods 6/01/2003 (Date created). [3] http:/ / www. nist. gov Further reading • Pyzdek, Thomas (2003). Quality Engineering Handbook (Second Edition ed.). New York: CRC. ISBN 0-8247-4614-7. External links • Run-Sequence Plot (
  3. 3. Article Sources and Contributors 3 Article Sources and Contributors Run chart  Source:  Contributors: Btyner, Craigkbryant, DanielPenfield, David Haslam, Davidelit, G716, Hooperbloob, Linas, Mdd, Melcombe, Michael Hardy, Nekohakase, Paul August, Pmc, Qwfp, 10 anonymous edits Image Sources, Licenses and Contributors Image:SimpleRunChart.jpg  Source:  License: Public Domain  Contributors: Mdd Image:Random Walk example.png  Source:  License: GNU Free Documentation License  Contributors: ChongDae, Darapti, Mdd, Ordoon, Toobaz, 1 anonymous edits Image:PD-icon.svg  Source:  License: Public Domain  Contributors: User:Duesentrieb, User:Rfl License Creative Commons Attribution-Share Alike 3.0 Unported http:/ / creativecommons. org/ licenses/ by-sa/ 3. 0/