In the lab handout, for the 8714b, there is a drill problem which adopts 1.93 as the effective dielectric constant. It is natural to assume that this then would be constant for the microstrip line provided for the lab experiment.

Please note that this is not the case. Referring to the table below from Roger Corporation where we get most of our substrates, from the thickness of the dielectric material we use (just over  ~1mm (no micrometers used here)) , the dielectric constant has to be 6.15 or 10.2.

Take your pick and justify them in getting me the right calculations as support of your lab results…

 
Table