Table 7 Results of two-step Heckman switching regression estimation on GSU water demand
From: Household demand and supply for clean groundwater in the Mekong Delta, Vietnam
Explanatory variable | Coefficient | z | P  >  z ab | Wald chi-square (8) | Number of observations |
|---|---|---|---|---|---|
Constant | 4.95 | 0.31 | 0.756 | Â | Â |
 Distance | −.008 | −0.48 | 0.623 |  |  |
 Sex | 5.14 | 1.05 | 0.295 |  |  |
 Age | −5.86 | −0.02 | 0.981 |  |  |
 Educationa | 5.55 | 1.71 | 0.087 |  |  |
 Occupation | 6.83 | 1.73 | 0.083 |  |  |
 Residence | −.002 | −1.31 | 0.192 |  |  |
 Family number | .002 | 0.19 | 0.849 |  |  |
 Income | .009 | 1.28 | 0.202 |  |  |
| Â | 18.76 | Â | |||
| Â | 195 | ||||