. Author manuscript; available in PMC: 2022 May 1.

Published in final edited form as: J Microbiol Methods. 2021 Mar 22;184:106186. doi: 10.1016/j.mimet.2021.106186

Table 2.

Relationships between E. coli culture and Method C across sites utilizing different data eligibility conditions.

						Theoretical Threshold @ 300^b
Selection criteria	N Sites	N Samples	Mean intercept	Mean slope	RSQ^a	Mean	Standard deviation
Quantitative results for both methods	96	4305	0.142	0.710	0.452	1.902	0.416
Quantitative results & statistical outliers removed	96	4043	0.089	0.720	0.574	1.873	0.329
Quantitative results, N ≥ 10 per site	83	4229	0.151	0.705	0.439	1.900	0.417
Quantitative results, N ≥ 10 per site, outliers removed	83	3987	0.094	0.717	0.563	1.870	0.330
Quantitative results, N ≥ 10 & culture ≥ 1 exceedance per site	57	3127	0.095	0.731	0.486	1.908	0.412
Quantitative results, N ≥ 10 & culture ≥ 1 exceedance per site, outliers removed	57	2955	0.061	0.732	0.589	1.876	0.335
Quantitative results, N ≥ 10, culture ≥ 1 exceedance & RSQ ≥ 0.6 per site	21	920	−0.073	0.763	0.623	1.817	0.351
Quantitative results, N ≥ 10, culture ≥ 1 exceedance & RSQ ≥ 0.6 per site, outliers removed	39	2092	−0.005	0.756	0.641	1.867	0.323

R-squared

Mean Method C log₁₀ copies/reaction estimates corresponding to 300 culturable E. coli MPN or CFU / 100 mL derived by simple linear regression model from composite data.