A-50 
Center Transect 
northing 
Figure 5.7. Simulated chlorophyll data, kriging estimates based on a sample of the 
simulated data, and conditionally simulated data where the simulation is conditioned 
on the data used obtain the kriging estimates. 
spatial trends similar to chlorophyll data from the Patuxent estuary, the confidence 
bands cover the true CFD in this case as well. Experiments that varied the sample 
size also produced confidence bands with good coverage. 
Additional evaluation of the confidence band procedure should include a series of 
confidence band coverage experiments to assess the true coverage rate in comparison 
to the nominal coverage rate (e.g., 95% in this example). This series of experiments 
should be conducted with simulated data where the simulations are designed to 
produce data with properties similar to the three primary assessment water quality 
parameters. 
appendix a 
The Cumulative Frequency Diagram Method for Determining Water Quality Attainment 
