  Exact pointer states are obtained for projection operator measurements
performed upon pre-selected (PS) and upon pre- and post-selected (PPS) quantum
systems. These states are used to provide simple exact expressions for both the
pointer spatial probability distribution profiles and the mean values of
arbitrary pointer observables associated with PS and PPS projection operator
measurements that are valid for any strength of the interaction which couples a
measurement pointer to the quantum system. These profiles and mean values are
compared in order to identify the effects of post-selection upon projector
measurement pointers. As a special case, these mean value results are applied
to the weak measurement regime - yielding PS and PPS mean value expressions
which are valid for any operator (projector or non-projector). Measurement
sensitivities which are useful for estimating weak measurement accuracies for
PS and PPS systems are also obtained and discussed.
