I think you need to talk to your instructors about getting new textbooks.
Here is diagram that Brad had up in the Archive>Cable section:
This conforms to what I always see. In this diagram, screen = ground, hot = signal(+), and cold = signal(-), just different terminology.
The balanced to unbalanced you show is correct btw, pin 2 (signal+) to the tip or ring, and then pins 1 and 3 tied together.