Fig. 1

Illustration of the growth inhibition assay (a). Calculated antimicrobial activity (b) directly from the assay including error bars (black diamonds) and curve fit with unknown error distribution (dotted line). Example of homoscedastic (blue triangles) and heteroscedastic (cyan asterisk) data (c). The dose–response curve and the corresponding parameters according to equation 1 for different curvatures are shown in color (d), with the relationship between the half growth of the indicator assay and the inflection point shown. Example of samples with increasing activity (e) and the resulting calculated dilution at half growth is shown (dashed line)