Transistor Voltage Divider Question
The 1k resistor is there to help make the \$I_C\$ current more stable with respect to changes in the transistor \$h_{FE}\$ parameter.  It's a kind of negative feedback.  Unfortunately, it lowers the AC gain, too.   If the frequency of the signal being amplified is not too low, there is usually a capacitor in parallel with this resistor to make it "invisible" for the AC signal while still providing stabilization on the DC \$I_C\$ current. However, since the amplifier is for audio signals, the capacitor would have to be fairly large and I guess that's the reason they've left it out.