. 2021 May 24;38(5):389–401. doi: 10.1089/ees.2020.0319

Table 2.

Mean and Median Differences, Standard Deviations, and Results of One-Tailed, Paired Sample t-Tests Comparing the Log₁₀-Transformed Concentrations of Escherichia coli and Enterococci in Samples Collected Directly Upstream and Directly Downstream of Homeless Encampments

Site	Indicator group	Log₁₀ difference in the upstream and downstream concentrations, log₁₀(C_downstream/C_upstream)			Sample size (N)	p^a
Site	Indicator group	Mean	Median	SD^b	Sample size (N)	p^a
Alvarado Creek	E. coli	0.15	0.12	0.16	8	0.016
Alvarado Creek	Enterococci	−0.04	−0.05	0.16	8	0.225
Forester channel	E. coli	0.59	0.39	0.65	8	0.018
Forester channel	Enterococci	0.24	−0.01	0.83	8	0.221
Fashion Valley	E. coli	1.15	1.04	0.56	4	0.013
Fashion Valley	Enterococci	0.67	0.62	0.31	4	0.011
Overall pooled (all three sites)	E. coli	0.53	0.30	0.60	20	0.006
Overall pooled (all three sites)	Enterococci	0.21	0.02	0.59	20	0.147

^{^a}

One-tailed, paired sample t-test of log₁₀-transformed concentrations from upstream and downstream samples. The null hypothesis is that upstream and downstream concentrations are equal; the alternative hypothesis is that downstream concentrations are greater.

^{^b}

SD of the log₁₀ difference between the concentrations in samples collected directly downstream and directly upstream.

SD, standard deviation.