Qualitative data that can be counted for recording and analysis. Examples include characteristics where the results are recorded in a simple yes/no fashion, such as acceptability of a hole diameter when measured with a go/no-go gage, or the presence of a
The sum of the values divided by the number of values (sample size). It is designated by a bar over the symbol for the values being averaged. This is called X-Bar.
X-Bar is the average of the X values within a subgroup.
X-Double Bar is the average of the subgroup averages.
Basic Statistical Methods
Applies the theory of variation through the use of basic problem-solving techniques and statistical process control. It includes control chart construction and interpretation (for both variables and attributes data) and capability analysis.
When the process average plus and minus the 3 sigma spread of the distribution of individuals is contained within the specification tolerance
(variables data), or when at least 99.73% of the individuals are within specification (attributes data) and capability analysis. Note that this can be determined only after the process is in statistical control.
The line on a control chart that represents the average or median value of the items being plotted (process average).
X = X-Bar = Average of the Subgroup Values
X = X-Double Bar = Average of the Subgroup Averages
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