February, 2003
© 2000, 2001, 2003 Scott S. Emerson, M.D., Ph.D.
In addition
to the summary measure, we must also choose a model for the
distribution of the data
Parametric
models assume a known shape for the distribution of the data
Semiparametric
models assume that the shape is similar in some way across
groups, but do not otherwise make any assumptions about the
exact shape of the distribution
Nonparametric
models make no assumption about how the shape of the
distribution might be similar (or different) across groups