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Measurements
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How-to

Xbar-R Chart Maker

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You can easily create a Xbar-R Chart online here! Simply copy your data into the table and select the measurements.

Xbar-R Chart Maker

The Xbar Chart will then be created for you online.

Create Xbar-R Chart online

Create a Xbar-R Chart online

In Statistical Process Control (SPC), an Xbar-R Chart is a type of control chart used to monitor the central tendency (Xbar) and the variation (R) of a process over time. It consists of two charts: the Xbar chart and the R chart.

How It Works:

  • Xbar Chart (Average Chart):
    • The Xbar chart displays the average or mean of a sample of measurements taken from the process at regular intervals.
    • Each point on the chart represents the average of a sample, and these averages are plotted over time on the horizontal axis.
    • A center line is drawn at the average of all the sample means, providing a reference for monitoring the process.
    • Upper and lower control limits are calculated based on the variation of the sample means and are typically set at a certain number of standard deviations from the center line.
  • R Chart (Range Chart):
    • The R chart displays the range of each sample, which is the difference between the maximum and minimum values within each sample.
    • Each point on the chart represents the range of a sample, and these ranges are plotted over time on the horizontal axis.
    • A center line is drawn at the average of all the sample ranges, providing a reference for monitoring the variation within the samples.
    • Upper and lower control limits are calculated based on the variation of the sample ranges and are typically set at a certain number of standard deviations from the center line.

Interpretation of the Xbar-R Chart involves analyzing both the Xbar chart and the R chart:

  • In the Xbar chart, if the sample averages fall within the control limits and show random variation around the center line, it indicates that the process is stable and under control.
  • In the R chart, if the sample ranges fall within the control limits and show random variation around the center line, it suggests that the variation within the samples is consistent and the process is stable.

The Xbar-R Chart is commonly used in industries such as manufacturing, healthcare, and finance to monitor and improve processes, identify potential issues early, and make data-driven decisions for process improvement.

Cite DATAtab: DATAtab Team (2025). DATAtab: Online Statistics Calculator. DATAtab e.U. Graz, Austria. URL https://datatab.net

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