Automatic Intra-Well Comparison (Script Command)

 

See Also:

Scripts

 

The automatic intra-well comparison is executed for each compliance well and for each parameter in the script.

 

Processing for the Automatic Intra-Well Comparison script command follows this sequence:

 

  1. Transform data to the original concentrations, and replace non-detects with 1/2 of the detection limit.

 

  1. If there are greater than 15% non-detects, a non-parametric test is used. Otherwise, normality is tested.

 

  1. If there are greater than 50 measurements, the Shapiro-Francia test for normality is applied. If there are fewer than 50 measurements, the Shapiro-Wilks test for normality is applied. If the normality passes, a parametric prediction limit is applied. If the normality test fails, the data set is log-transformed, and step 3 is applied to the natural logarithm of the data.

 

  1. If a parametric analysis is appropriate, the parametric prediction limit is applied as an intra-well comparison. If a non-parameter analysis is appropriate, the non-parametric prediction limit is applied.