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Re: st: RE: significance of mean and median


From   "Bastian Steingros" <Steingros@gmx.de>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: RE: significance of mean and median
Date   Mon, 24 Nov 2008 15:01:57 +0100

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
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