Step One: He found that the average “margin of error” of a New York City teacher was plus or minus 28 points.
Step Two: He found that the normal “margin of error” of a New York City educator was plus or minus 28 points.
Step Three: He found that the normal “margin of error” of a New York City educator was plus or minus 28 points. (Ravitch 270-71)
Step Four: Sean Corcoran set out to look at teacher evaluations in both New York and Houston. (Ravitch 270-71) His findings show that there was on average a boundary of error when evaluating students, which either added or subtracted 28 points.
Step Five: Sean Corcoran set out to look at teacher evaluations in New York and Houston (Ravitch 270-271). His findings show that the “average margin of error” of a typical New York teacher was “plus or minus 28 points” (Ravitch 270-271)
You clearly grasp the key concept, but forgot to include the full citation to the original source at the end of the exercise.