operationally measured or observed, and wherever possible keep the analysis simple, do
not rely on sophisticated techniques which are likely to be based on assumptions which
are questionable. The next chapter introduces parametric procedures which are based on
more restrictive assumptions but in certain circumstances are also more powerful than
binary and rank order statistical tests. They should be viewed not as alternatives to the
tests in this chapter but as complementary statistical procedures.
Inferences involving rank data 247