[Date Prev][Date Next][Thread Prev][Thread Next][Date index][Thread index]

RE: st: equivalence tests

From   "Steichen, Thomas J." <>
To   <>
Subject   RE: st: equivalence tests
Date   Tue, 10 Jul 2007 13:29:32 -0400

Joseph Coveney wrote:
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

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))

Yes, it is very much like that (even identically so), however, as noted 
by the author of -equim- in a post today, -equim- gives wrong answers 
when certain relatively common conditions occur, so cannot always be trusted.


CONFIDENTIALITY NOTE: This e-mail message, including any
attachment(s), contains information that may be confidential,
protected by the attorney-client or other legal privileges, and/or
proprietary non-public information. If you are not an intended
recipient of this message or an authorized assistant to an intended
recipient, please notify the sender by replying to this message and
then delete it from your system. Use, dissemination, distribution,
or reproduction of this message and/or any of its attachments (if
any) by unintended recipients is not authorized and may be

*   For searches and help try:

© Copyright 1996–2017 StataCorp LLC   |   Terms of use   |   Privacy   |   Contact us   |   What's new   |   Site index