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From | <richgold@ix.netcom.com> |
To | statalist@hsphsun2.harvard.edu |
Subject | Re: st: Output differences, Stata 11 vs Excel 2010 |
Date | Fri, 1 Nov 2013 14:35:32 -0400 (GMT-04:00) |
you do not tell us what you did (e.g., what was your exact Stata command); since, using -ttesti- on the last row of the Stata set below, I do not match your results (i.e., your p-value), you need to provide more information Rich -----Original Message----- >From: Yerik Kaslow <yerik.kaslow@gmail.com> >Sent: Nov 1, 2013 2:26 PM >To: "statalist@hsphsun2.harvard.edu" <statalist@hsphsun2.harvard.edu> >Subject: st: Output differences, Stata 11 vs Excel 2010 > >I apologize, copy+paste lead to sending before I had finished >displaying the data. Sorry! > >Hi Statalisters, > >I've noticed this difference several times before, and it's always >confused a troubled me a little. > >I have clinical trial data I'm analyzing, ttest output is below. The >means are nearly the same, but the standard deviations are different. >I've also noticed this also with p-values. The differences are always >small, but if it's right at the margin of significance, it can >obviously make a difference. > >Does anyone have insight as to why when I run tests of the exact same >data using Stata, then using Excel, I get slightly different results? > >Any insight is appreciated. Thus far I've been taking Stata's output >over Excel's. I apologize for the bunching together of the output, >plain text mode is what it is. > >Thanks in advance, > >Excel Output: > >N Int N Con Total N Mean Int Mean Con Diff Int Con SD Int SD Con Pvalue = >CD1 68 58 126 6.49 6.45 0.04 2.70 2.21 0.9344 >CD2 68 58 126 7.65 7.41 0.23 2.27 2.07 0.5539 >CD3 68 58 126 8.01 7.90 0.12 2.12 2.06 0.7542 >CD4 68 58 126 7.29 7.22 0.07 2.34 2.01 0.8597 >CD5 68 58 126 7.74 6.45 1.29 2.13 2.49 0.2262 >CD6 68 58 126 7.74 7.31 0.42 2.15 2.24 0.2841 > >Stata Output: > >N Int N Con Total N Mean Int Mean Con Diff Int Con SD Int SD Con Pvalue = >CD1 68 58 126 6.49 6.45 0.04 2.37 1.97 0.9252 >CD2 68 58 126 7.65 7.41 0.23 2.14 1.66 0.5012 >CD3 68 58 126 8.01 7.90 0.12 2.00 1.82 0.7313 >CD4 68 58 126 7.29 7.22 0.07 2.11 1.77 0.8425 >CD5 68 58 126 7.74 6.45 1.29 1.99 2.29 0.1015 >CD6 68 58 126 7.74 7.31 0.42 1.89 1.98 0.2223 > > >-- >Yerik Kaslow >yerik.kaslow@gmail.com >* >* For searches and help try: >* http://www.stata.com/help.cgi?search >* http://www.stata.com/support/faqs/resources/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/faqs/resources/statalist-faq/ * http://www.ats.ucla.edu/stat/stata/