This notion of process is, of course, inherent in the statistician’s conception of a
population, and we expect that most experts move between the process and
population perspectives with little difficulty or awareness.5 However, for students
new to the study of statistics, the choice of perspective could be critical. To illustrate
more fully what we mean by reasoning about processes and their central tendencies,
we discuss recent results of the National Assessment of Educational Progress
(NAEP).