Why observers in B observe these relativistic, virtual phenomena
     Observers in B reach incorrect conclusions based on events they see as reference frame B moves relative to A. At time tA=0 s (when the clocks in A displayed 0 s) the Ax=.6 mark was at the Bx=.75 mark where the Bx=.75 clock displayed -(.75·.6) or -.45 s (via the above RULE and because the Bx=0 clock displayed 0 s). At time tA=1 s the Ax=.6 mark is at the Bx=0 mark and clock displaying .8 s (as shown). Therefore, observers in B see the Ax=.6 mark move from Bx=.75 at -.45 s to Bx=0 at .8 s and conclude incorrectly that the Ax=.6 mark moved .75 ls in (.8+.45) or 1.25 s and that the velocity of B relative to A must be (.75/1.25) or .6 c.
     Observers in B see the Bx=0 mark move from Ax=0 to Ax=.6 while the Bx=0 clock advanced .8 s. The observers conclude that the Bx=0 mark moved (.6 c · .8 s) or .48 ls relative to A and that a distance unit in A is (.48/.6) or .8 times the length of a distance unit in B. This "relativistic length contraction" is exactly what the observers expect according to Eq. (3).
     Observers in B see the Ax=.6 clock advance 1 s as it moves from the Bx=.75 clock displaying -.45 s to the Bx=0 clock displaying .8 s, and conclude that clocks in A advance 1 s while clocks in B advance 1.25 s and that the rate of clocks in A is (1/1.25) or .8 times the rate of clocks in B. This "relativistic time dilation" is what the observers expect according to Eq. (3).
     These events, seen by observers in B, were chosen for ease of explanation, but observers in B will determine the same slowness of clocks in A and shortness of distances marked along the x axis of A regardless of which clocks and distance marks the observers in B choose to observe. The reader can confirm this by determining other sets of events that observers in B will see as reference frames A and B move relative to one another.

Why observers in reference frame A observe real phenomena
     Observers in A observe the real phenomena occurring in the medium because the units of time and distance in A are absolute units and because the speed of light in A is constant. Based on the events they see, observers in A determine that the rate of clocks in B is .8 times the rate of clocks in A and that the distances marked along the x axis of B are .8 times the distances marked in A. These observations in A are correct, but the observers in A and B do not realize this.

Note: The preceding multiple causes for observed "length contraction" and "time dilation" are consequences of Premise I and every observer's belief that the speed of light is constant in her reference frame. Because these observed phenomena are due to combinations of the causes, and because the causes can differ from one reference frame to another (e.g. A vs. B in Fig. 1), the causes are not easily grasped. If the reader cannot now explain clearly the above multiple causes for observed "relativistic length contraction and time dilation," it is recommended that the preceding sections be reviewed until the causes are clearly in mind.