TABLE 5.

Analysis of assumed t-distributed RS and ES at the Wahnbach gauge for independence from each other, using the one-sided t test for two spot checks with different variances (1997 data)

Parameter	RS (n = 25)			ES (n = 14)			t test t (empirical)	df (empirical)	P(α) (one sided)a
	Arithmetic mean	Maximum	SD	Arithmetic mean	Maximum	SD
Turbidity (NTU)	11.45	36.00	8.19	56.99	125.30	31.12	5.372	14.173	0.000b
pH	7.55	8.00	0.25	7.33	7.50	0.16	3.404	38.362	0.001c
Runoff (liters/s)	459.54	2,118.00	448.31	1,040.46	2,747.00	608.07	3.130	22.227	0.002b
Nitrate (mg/liter)	17.22	33.90	6.82	10.43	20.10	5.27	3.466	35.378	0.001c
Nitrite (mg/liter)	0.10	0.40	0.09	0.09	0.14	0.04	0.469	38.337	0.321
Ammonia (mg/liter)	0.15	1.46	0.35	0.34	1.70	0.61	1.061	18.610	0.151
Total phosphorus (mg/liter)	0.15	0.62	0.16	0.25	0.50	0.18	1.610	26.392	0.060
Borate (mg/liter)	0.13	0.27	0.06	0.18	0.35	0.08	2.218	23.985	0.018b
CC 20°C (CFU/ml)	2,132.88	16,500.00	3,449.77	34,542.86	77,000.00	22,355.75	5.389	13.401	0.000b
CC 37°C (CFU/ml)	468.40	1,850.00	378.73	8,547.14	14,700.00	3,344.97	9.005	13.216	0.000b
E. coli (CFU/100 ml)	913.28	5,100.00	1,252.98	19,471.43	34,500.00	11,870.37	5.832	13.187	0.000b
Coliforms (CFU/100 ml)	13,714.80	74,000.00	20,136.04	264,428.57	1,180,000.00	417,695.21	2.244	13.039	0.021b
Fecal streptococci (CFU/100 ml)	266.40	2,200.00	443.30	20,457.14	77,000.00	25,138.54	3.005	13.005	0.005b
C. perfringens (CFU/100 ml)	190.92	900.00	226.01	880.00	2,500.00	900.59	2.814	14.065	0.007b
Giardia (cysts/100 liters)	2.13	9.10	2.48	10.60	21.60	7.25	4.232	14.980	0.000b
Cryptosporidium (oocysts/100 liters)	3.60	23.10	6.37	27.48	147.10	37.69	2.352	13.482	0.018b

^aValues were considered significantly different if the P(α) value was <0.05.

^bThe ES values were significantly greater than the RS values.

^cThe ES values were significantly less than the RS values.