Tests of statistical hypotheses can be based on either of two critical valu
es: the Type I critical value or the size-corrected critical value. The for
mer usually depends on unknown population parameters and cannot be evaluate
d exactly in applications, but it can often be estimated very accurately by
using the bootstrap. The latter does not depend on unknown population para
meters but is likely to yield a lest with low power. The critical values us
ed in most Monte Carlo studies of the powers of tests are neither Type I no
r size-corrected. They are irrelevant to empirical research. (C) 2000 Elsev
ier Science S.A. All rights reserved.