  Deviations between the form of trajectory assumed in a fit to a set of
measurements and the actual form of the trajectory can give rise to sequential
correlations in the residuals from the fit. These correlations can provide a
more powerful goodness-of-fit test than that based on the minimum chi-square
from a least squares fit. The use of this additional information is explored in
the context of several common trajectory errors (e.g. decays in flight)
encountered in charged particle tracking.
