Table 2.

Welch’s two-sample t test analysis

	Site 1		Site 2		Site 3		Site 4
	Sample A	Sample B	Sample A	Sample B	Sample A	Sample B	Sample A	Sample B
Mean	241.65	134.25	159.12	65.77	144.86	57.45	75.78	63.20
Observations	36	35	36	35	36	35	36	35
Hypothesized mean difference	0		0		0		0
Degree of freedom	62		38		40		42
95% confidence interval	(71.05, 143.75)		(69.45, 116.99)		(63.14, 111.65)		(1.09, 24.05)
t-statistic	5.91		7.94		7.28		2.20
P (T ≤t) one-tail	0.00000015		0.0000000014		0.0000000074		0.03
t Critical one-tail	1.67		1.68		1.68		1.68