Fig. 6.

Same as Figure 1, with additional boxplots showing the residuals when non-detects are replaced with 35 rather than 40. Here, Ct values >35 are also replaced by a value of 35. By replacing non-detects with a value of 35 rather than 40, the distribution of the residuals is far more similar between those in which the Ct values were observed and those containing a non-detect. However, this does not imply that one should replace non-detects with a value of 35. Such an approach makes very strong assumptions about the missing data mechanism and would require one to discard observed Ct values >35