Quality AnalytiX organizes tags and historical values using the following three levels of sampling:
Samples represent actual measurements from a device and therefore contain collected or merged raw values. This level of sampling provides the most detail, but it also presents the most variation and complexity.
Some sample values appear in the following chart:
A subgroup represents a set of samples belonging to the same measurement. Therefore, each serves as a summary of that measurement for a particular device. This grouping process reduces measurement variability, allowing you to see long-term trends more easily.
Some subgroup values appear in the chart below. Note that these values represent 5-value averages of the samples that appear in the Samples section of this topic (and are therefore x-bar summaries of the original sample values).
A group represents a set of subgroups, further consolidating your device's measurement data. Each of these collections serves as a "super-summary" of a particular measurement and allows you to view a single value to assess the performance of an entire production batch.
Some group values appear in the chart below. Note that these values represent 5-value averages of the subgroups that appear in the Subgroups section of this topic (and are therefore double-x-bar summaries of the original sample values).
See also: