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st: How may I compute standard errors and/or confidence intervalsfor the following functions


From   "Ben Dwamena" <bdwamena@med.umich.edu>
To   <statalist@hsphsun2.harvard.edu>
Subject   st: How may I compute standard errors and/or confidence intervalsfor the following functions
Date   Sun, 09 Dec 2007 00:47:00 -0500

Dear Statalisters,
I am working  with normally distributed test results in patients with and without a disease condition related to alpha (accuracy parameter) and beta (threshold parameter) such that:

alpha = (2*pi/sqrt(3))*[ (mu_nd - mu_d)/(sigma_nd + sigma_d)]

beta = (sigma_nd - sigma_d)/(sigma_nd + sigma_d)

where mu_nd and sigma_nd  are the mean and standard deviation of test results in N_nd non-diseased patients 

and mu_d and sigma_d  are the mean and standard deviation of test results in N_d diseased patients.


How may I compute  standard errors and/or confidence intervals for alpha and beta?


Thanks for your assistance.

Ben



Ben Adarkwa Dwamena, MD

Assistant Professor of  Radiology
Division of Nuclear Medicine
Department of Radiology
University of Michigan Health Systems
B1G505 UH SPC 5028
1500 E. Medical Center Drive
Ann Arbor, MI  48109-5028


bdwamena@umich.edu

http://sitemaker.umich.edu/metadiagnosis



Staff Physician
D748 Nuclear Medicine Service (115), 
VA Ann Arbor Health Care System
2215 Fuller Road
Ann Arbor, MI 48105
734-845-3775 Phone
734-845-3252 Fax



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