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From |
Tim Wade <wadetj@gmail.com> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: predict after logit |

Date |
Wed, 11 Jul 2012 17:27:48 -0400 |

apologies, the first segment of code should read: sysuse auto.dta xtile hiprice=price, nq(2) logistic foreign hiprice mpg margins, by(hiprice) On Wed, Jul 11, 2012 at 5:26 PM, Tim Wade <wadetj@gmail.com> wrote: > If I understand what you are asking, I think margins does this: > > margins, by(hiprice) > sysuse auto.dta > xtile hiprice=price, nq(2) > logistic foreign hiprice mpg > margins, by(hiprice) > > > ------------------------------------------------------------------------------ > | Delta-method > | Margin Std. Err. z P>|z| [95% Conf. Interval] > -------------+---------------------------------------------------------------- > hiprice | > 1 | .2162162 .0557663 3.88 0.000 .1069163 .3255161 > 2 | .3783784 .0681487 5.55 0.000 .2448094 .5119474 > ------------------------------------------------------------------------------ > > > note this margin estimates are the same as the means of phat: > > logistic foreign hiprice mpg > predict phat > tabulate hiprice, summ(phat) > > > 2 quantiles | Summary of Pr(foreign) > of price | Mean Std. Dev. Freq. > ------------+------------------------------------ > 1 | .21621622 .23645819 37 > 2 | .37837838 .25520846 37 > ------------+------------------------------------ > Total | .2972973 .25759862 74 > > Tim > > > On Wed, Jul 11, 2012 at 1:01 PM, Sara Borelli <saraborelli77@gmail.com> wrote: >> Hi all, >> I am running a logit model to obtain a predicted probability for each >> individual (phat_i) using predict, pr command . >> >> I have to calculate the average of this prediction within some >> categories of a variable x: >> mean_phat_i=mean( phat_i) by(x) >> and obtain standard errors and confidence interval for this mean. >> >> I know I can use adjust for this purpose, but I also need to calculate >> standard errors/confidence intervals for mean_phat_i >> >> Thanks in advance for any insight >> >> Sara >> * >> * 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/

**Follow-Ups**:**Re: st: predict after logit***From:*Sara Borelli <saraborelli77@gmail.com>

**References**:**st: predict after logit***From:*Sara Borelli <saraborelli77@gmail.com>

**Re: st: predict after logit***From:*Tim Wade <wadetj@gmail.com>

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