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Re: st: equivalence tests


From   Joseph Coveney <jcoveney@bigplanet.com>
To   Statalist <statalist@hsphsun2.harvard.edu>
Subject   Re: st: equivalence tests
Date   Wed, 11 Jul 2007 01:04:58 +0900

Ronan Conroy wrote:

Has anyone cooked up a tost (two one-sided tests) ado?

--------------------------------------------------------------------------------

Isn't it something like that below?  (Also, "test1:" and "test2:" reported
by -equim- are the TOST.)

Joseph Coveney

clear
set more off
sysuse auto
ttest price, by(foreign) level(90)
local delta = 0.2 * r(mu_1) // Domestic is "reference group"
* Option 1:  By inspection, declare therapeutic equivalence if
* 90% CI is contained within the interval -delta to +delta
display in smcl as result `delta'
* Option 2:  Schuirmann's Two One-sided Tests (TOST);
* reject at alpha = 10% (5%, one-sided)
* (Note: TOST is operationally equivalent to Option 1 above)
local difference = r(mu_1) - r(mu_2) // mu_reference - mu_test
display in smcl as result 2 * ttail(r(df_t), (`delta'-`difference')/r(se))
display in smcl as result 2 * ttail(r(df_t), (`delta' + `difference')/r(se))
exit

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