Table 2.
Proportions of high level of constituents (percentage above thresholds) among four groups in Cabot data
|
Symbols |
Upland far % (n/N) |
Upland near %( n/N) |
Valley far % ( n/N) |
Valley near % (n/N) |
p-value* | FDR- adjusted p- value # |
|---|---|---|---|---|---|---|
| SO4 | 19.69 (25/127) | 34.48 (20/58) | 13 (13/100) | 54.29 (76/140) | <0.0001 | 0.0003 |
| Ba | 28.00(91/329) | 15.25 (18/118) | 33.21 (91/274) | 15.22 (28/184) | <0.0001 | 0.0003 |
| CH4 | 2.54 (18/710) | 2.38 (3/126) | 13.17 (88/668) | 7.69 (15/195) | <0.0001 | 0.0003 |
| Cond | 18.67 (98/525) | 21.31 (13/61) | 27.95 (135/483) | 42.74 (50/117) | <0.0001 | 0.0003 |
| Fe | 17.63 (58/329) | 25 (29/116) | 20.82 (56/269) | 41.44 (75/181) | <0.0001 | 0.0003 |
| Cl | 20.12 (65/323) | 29.82 (34/114) | 21.98 (60/273) | 36.36 (68/187) | 0.0003 | 0.0006 |
| TDS | 19.57 (63/322) | 27.35 (32/117) | 24.54 (67/273) | 35.11 (66/188) | 0.0003 | 0.0006 |
| Mn | 14.24 (47/330) | 18.8 (22/117) | 28.83 (79/274) | 21.98 (40/182) | 0.0006 | 0.0011 |
| Ca | 25.4 (32/126) | 24.56 (14/57) | 15.15 (15/99) | 36.03 (49/136) | 0.0161 | 0.0250 |
| Na | 22.22 (28/126) | 33.33 (19/57) | 37 (37/100) | 28.68 (39/136) | 0.0293 | 0.0410 |
| Turb | 16.82 (36/214) | 20.93 (18/86) | 22.14 (31/140) | 28.4 (46/162) | 0.0425 | 0.0541 |
| Mg | 25.16 (81/322) | 32.23 (39/121) | 24.39 (70/287) | 19.08 (33/173) | 0.1226 | 0.1430 |
| Alk | 22.05 (28/127) | 31.03 (18/58) | 29 (29/100) | 28.78 (40/139) | 0.3341 | 0.3598 |
| Pb | 26.19 (33/126) | 28.07 (16/57) | 28.28 (28/99) | 25 (34/136) | 0.9019 | 0.9019 |
*
p-value was from Chi-square test for group differences in proportion of high levels.
#
False discovery rate, defined as the multiple tests adjusted p-values using the approach (Benjamini and Hochberg, 1995) to control for false positive error rate.