The hypotheses for an equivalence test are
where and
are the lower and upper bounds specified in the TOST
option in the PROC TTEST
statement, and
is the analysis criterion (mean, mean ratio, or mean difference, depending on the analysis). Following the two one-sided
tests (TOST) procedure of Schuirmann (1987), the equivalence test is conducted by performing two separate tests:
and
The overall p-value is the larger of the two p-values of those tests.
Rejection of in favor of
at significance level
occurs if and only if the 100(1 – 2
)% confidence interval for
is contained completely within
. So, the 100(1 – 2
)% confidence interval for
is displayed in addition to the usual 100(1 –
)% interval.
For further discussion of equivalence testing for the designs supported in the TTEST procedure, see Phillips (1990); Diletti, Hauschke, and Steinijans (1991); Hauschke et al. (1999).