xiii
List of Figures
Figure 4.1 Schematic illustration of precision and accuracy.
101
Figure 4.2 Results from analysis of low-concentration QC samples for
nitrate analysis. The target value of the control sample is
represented by the central line; the upper and lower dotted
and dashed lines represent the range of satisfactory data
based on the DQOs.
116
Figure 4.3 Results from analysis of low-concentration QC samples for
sulfate analysis. The target value of the control sample is
represented by the central line; the upper and lower dotted
and dashed lines represent the range of satisfactory data
based on the DQOs.
116
Figure 5.1 Example plot of cation sum versus anion sum. There are
two potential outliers that warrant further investigation to
determine if an error was made in analyzing or reporting
the concentration of one or more ions for these two samples. 128
Figure 5.2 Example plot to examine the relationship between
calculated and measured conductivity. There are two
obvious outliers that warrant further investigation
to determine if an error was made in analyzing or
reporting the concentration of one or more ions for those
two samples.
133
Figure 5.3 Example plot of calculated carbonate alkalinity
versus laboratory-titrated ANC. In general, calculated
carbonate alkalinity is slightly lower than measured ANC
(as it should be). There are no obvious outliers in this
hypothetical example.
134
Figure 5.4 Example histogram plot of patterns in DOC concentration
in streams within a particular region. The data are not
normally distributed; rather, they are skewed toward lower
concentrations (≤3 mg/L).
136
List of Figures
Figure 4.1 Schematic illustration of precision and accuracy.
101
Figure 4.2 Results from analysis of low-concentration QC samples for
nitrate analysis. The target value of the control sample is
represented by the central line; the upper and lower dotted
and dashed lines represent the range of satisfactory data
based on the DQOs.
116
Figure 4.3 Results from analysis of low-concentration QC samples for
sulfate analysis. The target value of the control sample is
represented by the central line; the upper and lower dotted
and dashed lines represent the range of satisfactory data
based on the DQOs.
116
Figure 5.1 Example plot of cation sum versus anion sum. There are
two potential outliers that warrant further investigation to
determine if an error was made in analyzing or reporting
the concentration of one or more ions for these two samples. 128
Figure 5.2 Example plot to examine the relationship between
calculated and measured conductivity. There are two
obvious outliers that warrant further investigation
to determine if an error was made in analyzing or
reporting the concentration of one or more ions for those
two samples.
133
Figure 5.3 Example plot of calculated carbonate alkalinity
versus laboratory-titrated ANC. In general, calculated
carbonate alkalinity is slightly lower than measured ANC
(as it should be). There are no obvious outliers in this
hypothetical example.
134
Figure 5.4 Example histogram plot of patterns in DOC concentration
in streams within a particular region. The data are not
normally distributed; rather, they are skewed toward lower
concentrations (≤3 mg/L).
136