Statistics Groups

And Excluding Containers from Statistical Analysis

See Also:

Export to ChemStat 

Blind Duplicates 

ChemPoint allows you to assign each sample container to one of four statistics groups, or to exclude a container from statistical analysis. It is important to remember that statistics groups are assigned at the container level. If using the Dates and Locations View, you assign a statistics group to a sampling date or location, the assignment is made for all existing containers of that date or location. Any containers added after the assignment must be reassigned to the correct group.

  Statistics group assignments are associated with containers, not with sampling dates or sampling locations.

Why Use Statistics Groups?

Statistics groups allow you to group containers for statistical analysis, either by location, or by time. Grouping by location is useful because it allows you to group containers based on the monitoring zone or aquifer in which they are included. For example, you may choose to specify upper aquifer containers in statistics group 1 and lower aquifer containers in statistics group 2. You can then export each aquifer to ChemStat individually.

Grouping by time is useful because it allows you to exclude a particular time period from statistical analysis. For example, you may want to exclude all samples greater than 10 years old.

Why Exclude a Container from Statistics?

It is useful to exclude individual containers from statistical analysis for several reasons.

  1. The container may be a blind duplicate collected for quality control, and not intended to be analyzed.
  2. The quality of the analysis of the container may be questionable.
  3. The container may be a verification sample not intended for statistical analysis.

There may be other reasons specific to your particular monitoring situation.