Universal Voltage Divider Bias Circuit with both BJT and JFET
The current into the base of the BJT is about \$\beta\$ (100) times smaller than the current through the emitter/collector. The upshot of this is that the effect of the 1k2 resistor as seen at the base can be regarded as the same as a grounded base resistor that is 100 times higher or 120kohm. This will make Vg a few percent lower.