Quantile Non-Parametric Test

 

See Also:

Slippage Non-Parametric Test

Wilcoxon Non-Parametric Group Comparison

Gehan's Non-Parametric Test

 

Description:

 

The Quantile test is provided in the U.S. Navy 1999 Guidance Document as a test to determine if compliance point measurements are statistically elevated when compared to background. It is a non-parametric test, and therefor a normal distribution is not required and the test is suitable for any number of non-detects. In ChemStat, the test can be performed at the 99% or 95% confidence levels.

 

Use:

 

In ChemStat, the Quantile test can be run in two ways:

 

  1. It can be used to determine if compliance point observations as a group are statistically elevated when compared to background point measurements as a group, however, it can not determine which individual monitoring points are elevated. This is how the test is presented in the U.S. Navy 1999 Guidance Document.

 

  1. It can be used as an intra-well comparison to determine if a single compliance well is elevated when compared to all background measurements, however, a large number of data points from the compliance well may be required. This implementation is more appropriate for RCRA regulated sites.

 

Use the right-click menu in ChemStat to select the confidence level and the well comparison type.

 

 

Remarks:

 

For use in RCRA monitoring sites when detecting a statistical significance in individual compliance wells, a large number of samples may be required to perform a suitable analysis. Pay attention to the required sample sizes on page 67 of the U.S. Navy 1999 Guidance.

 

ChemStat obtains r and k from Tables A11 and A13 in the U.S. Navy 1999 Guidance. Therefore, ChemStat can not calculate values of r and k for n and m that exceed the range of these tables. For intermediate values of n and m not listed in the table, ChemStat uses the next highest value of n and m for which there is a value in the table.

 

Also note that the Type I error rate of 0.01 or 0.05 is approximate. Tables A11 and A13 in the U.S. Navy 1999 Guidance Document provide precise Type I error rates.