Despite these differences, their concentrations were strongly correlated, with Spearman correlation coefficients > 0.75 for comparisons among the SAM sites and > 0.89 for comparisons of the individual site concentrations with the mean concentration across the sites.
Although it may seem more appropriate because of the "varying mean" concentration across the contiguous U.S. assumption, universal kriging requires a predetermined set of "exploratory variables" to explain the varying means.
Based on previous work in mice (Southworth et al., 2009) that identified changes in network connectivity with age, we hypothesized that for some metabolites, diet might not change the mean concentration across samples, but instead might influence their correlation with other metabolites.
For BDE-100 and BDE-153, we observed a moderate increase in mean concentration across these three strata as reported fish consumption increased; this was also true for BDE-85 and BDE-183, where a greater proportion of the samples were measured < LOD.
The daily mean was then calculated from the 24-hr specific average concentrations across the monitors.
These results are consistent with the strong correlations among the sites' PM2.5 concentrations, with Spearman correlation coefficients > 0.87 for pairwise comparisons of the 4-hr concentrations at the individual sites with the 4-hr across-site mean concentrations.
With the exception of canakinumab pharmacokinetics, temporal profiles of mean concentrations show little differences across dose levels.
Mean concentrations of Cu in vegetables across the 10 vegetable farming sites were varied and all below the RML standard (Table 3).
Mean concentrations ranged from 18 24 μg/m3 across EPA monitors during non-DNC weeks, versus 12 17 μg/m3 during the DNC (30 36% lower).
Chi-square test and Student t-test were used to examine the difference in the proportion of detecting p,p´-DDT in blood and the mean concentrations of p,p´-DDE across demographic factors, respectively.
