True or False?
(a) The main purpose of background sampling is to compare constituent concentrations between areas affected and unaffected by site activities; (b) Background sampling should always be a part of every site investigation; (c)Background substances can only arise from naturally occurring processes; (d) A commonly used method for comparing site and background constituent concentrations when the data are not normally distributed and/or contain outliers is the Wilcoxon rank sum two-sample test; (e) It is also possible to perform the site versus background comparison by comparing the upper tolerance limit computed from site data with individual background concentrations; (f) Both the quantile–quantile plot and the double quantile plot are useful graphical tools for visually comparing the site and background data distributions; (g) The quantile–quantile plot and the double quantile plot are duplicative, as they essentially serve the same function; (h) The mean or median contaminant concentration computed from a data sample is commonly used as the EPC for exposure risk assessment; (i) A COPC is a contaminant for which the EPC exceeds the AL or other regulatory screening value; (j) If the EPC is higher than the AL, but hypothesis tests indicate no significant difference between the site and background contaminant populations, the contamination may not be attributable to site-related activities.
