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| From | Sara Borelli <sborelli@impaqint.com> |
| To | "statalist@hsphsun2.harvard.edu" <statalist@hsphsun2.harvard.edu> |
| Subject | st: RE: RE: sampsize formula |
| Date | Thu, 3 Nov 2011 15:40:06 -0400 |
Thank you Sarah The problem is that we do not have access to the manuals right now, but the reference helps a lot thanks Sara Borelli, Ph.D. Research Associate IMPAQ International, LLC 1425 K St. NW, Suite 650 Washington, DC 20005 ****************************** Phone: 443.367.0088 Ext. 2234 Direct: 443.283.6231 Fax: 202.289.0024 Email: sborelli@impaqint.com Web: www.impaqint.com This e-mail and any attachments are intended only for the named recipient(s) and may contain information that is legally privileged, confidential, or exempt from disclosure under applicable law. If you have received this message in error, or are not the named recipient(s), you may not retain copy or use this e-mail or any attachment for any purpose or disclose all or any part of the contents to any other person. Any such dissemination, distribution or copying of this e-mail or its attachments is strictly prohibited. Please immediately notify the sender and permanently delete this e-mail and any attachment from your computer. -----Original Message----- From: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Sarah Edgington Sent: Thursday, November 03, 2011 3:36 PM To: statalist@hsphsun2.harvard.edu Subject: st: RE: sampsize formula Do you have access to the Stata base reference manuals? Typically the manuals contain detailed information on the formulas used to implement a command. The manual entry for -sampsi- is no exception. It's in the section titled "Methods and formulas" near the end of the entry. Hope that helps. -Sarah -----Original Message----- From: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Sara Borelli Sent: Thursday, November 03, 2011 12:12 PM To: statalist@hsphsun2.harvard.edu Subject: st: sampsize formula Hello Statalist members, I would like to know the exact formula beyond the sampsi command to calculate the sample size of two groups using comparison of means : sampsi m1 m2, sd1() sd2() power () alpha() the output gives me the sample size of the two groups, n1 and n2, but I would need the exact mathematical formula Thanks for any suggestion Sara Borelli * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/ * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/ * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/