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From |
"Bastian Steingros" <Steingros@gmx.de> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: RE: st: RE: significance of mean and median |

Date |
Mon, 24 Nov 2008 16:55:52 +0100 |

Yes I was wrong, the mean ttest example makes it very clear. thanks a lot -------- Original-Nachricht -------- > Datum: Mon, 24 Nov 2008 15:15:42 +0100 > Von: "Martin Weiss" <martin.weiss1@gmx.de> > An: statalist@hsphsun2.harvard.edu > Betreff: RE: st: RE: significance of mean and median > Line for the server... > > You probably wanted to say that "the CI did not overlap zero". Regarding > the > proper interpretation of statistical tests, you should consult any > undergraduate statistics textbook. The 5% level means that your rejection > of > H0 will be wrong in 5% of the times you conduct this test. Note the > parallels between -mean- and -ttest- > > ******* > sysuse auto, clear > replace mpg=mpg-20 > ttest mpg=0 > mean mpg > ****** > > -ttest- output also gives you one-sided tests. Your question regarding > whether you can conclude that the mean is negative is answered by the > leftmost output of -ttest-. > > Regarding your -signtest-, do not try to reinvent the wheel. Stata > provides > a whole submenu of regression diagnostics which can be employed to > discriminate between two competing models... > > > HTH > Martin > > > -----Original Message----- > From: owner-statalist@hsphsun2.harvard.edu > [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Bastian > Steingros > Sent: Monday, November 24, 2008 3:02 PM > To: statalist@hsphsun2.harvard.edu > Subject: Re: st: RE: significance of mean and median > > Hi Martin, > > Using *mean* for several variables, stata has provided result like > mean_var_x=-0.056 and the upper end of the CI did not overlap zero. Given > a > 95% CI, does the result indicate that the mean of var_x > is negative at the 5% level (1% when used a 99% CI)? > > Is signtest not appropriate to compare the median inaccuracies of model 1 > +2 > or more generally to the medians of two variables? > > b > > > > -------- Original-Nachricht -------- > > Datum: Mon, 24 Nov 2008 13:46:42 +0100 > > Von: "Martin Weiss" <martin.weiss1@gmx.de> > > An: statalist@hsphsun2.harvard.edu > > Betreff: st: RE: significance of mean and median > > > > > Line for the server... > > > > On the second part, without judging the appropriateness of your > procedure, > > "(GDP_predicted - GDP)" looks like a straightforward residual to me, > > available from -predict-, which would generate a new variable, ready to > be > > divided by "GDP" with -replace-. Afterwards -ttest- compares means and > > -median- compares medians... > > > > HTH > > Martin > > > > > > -----Original Message----- > > From: owner-statalist@hsphsun2.harvard.edu > > [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Bastian > > Steingros > > Sent: Monday, November 24, 2008 12:56 PM > > To: statalist@hsphsun2.harvard.edu > > Subject: st: significance of mean and median > > > > Hello everybody, > > > > I have this problem: > > > > After creating the descriptive statistics of my sample I want to show > that > > the mean of a certain variable is statistically significant. > > For example the mean of var1 is 0,45. Now I want to show that the > positive > > sign is significant. > > Is ttest the appropriate way to do so? > > > > Moreover, in another sample I want to predict the GDP using two > different > > regression models. > > Finally, I want to compare the predicted values with the real GDP, that > > is, > > I will compare the mean and the median of the inaccuracy. > > Inaccuracy is defined as (GDP_predicted - GDP)/GDP > > > > Is there a way to show that the median (mean) inaccuracies of the two > > models > > are statistically different from each other? > > > > may be *signtest*??? > > > > thanks > > > > bastian s > > -- > > Sensationsangebot nur bis 30.11: GMX FreeDSL - Telefonanschluss + DSL > > für nur 16,37 Euro/mtl.!* http://dsl.gmx.de/?ac=OM.AD.PD003K11308T4569a > > * > > * 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/ > > -- > Sensationsangebot nur bis 30.11: GMX FreeDSL - Telefonanschluss + DSL > für nur 16,37 Euro/mtl.!* http://dsl.gmx.de/?ac=OM.AD.PD003K11308T4569a > * > * 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/ -- Sensationsangebot nur bis 30.11: GMX FreeDSL - Telefonanschluss + DSL für nur 16,37 Euro/mtl.!* http://dsl.gmx.de/?ac=OM.AD.PD003K11308T4569a * * 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/

**References**:**st: significance of mean and median***From:*"Bastian Steingros" <Steingros@gmx.de>

**st: RE: significance of mean and median***From:*"Martin Weiss" <martin.weiss1@gmx.de>

**Re: st: RE: significance of mean and median***From:*"Bastian Steingros" <Steingros@gmx.de>

**RE: st: RE: significance of mean and median***From:*"Martin Weiss" <martin.weiss1@gmx.de>

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