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From |
"Martin Weiss" <martin.weiss1@gmx.de> |

To |
<statalist@hsphsun2.harvard.edu> |

Subject |
AW: st: AW: why is this graph all over the place? |

Date |
Mon, 21 Sep 2009 22:26:29 +0200 |

<> " I corrected the matrix to replace marg=A[1,57] in `i'" Just give me a hint why you did that... You could simply pick one of the values of your varmain, and plug it into -mfx, such as seen here for the value you mentioned earlier. Then list the contents of the matrix with the marginal effects. ************* mfx, var(varmain) at(varmain=42.6) mat list e(Xmfx_dydx) ************* and show us the output... HTH Martin -----Ursprüngliche Nachricht----- Von: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] Im Auftrag von Nirina F Gesendet: Montag, 21. September 2009 22:14 An: statalist@hsphsun2.harvard.edu Betreff: Re: st: AW: why is this graph all over the place? Replacing it with -levelsof- made it work! Thanks. But I don't know why the marginal effects are not recorded. However, I corrected the matrix to replace marg=A[1,57] in `i' Thanks in advance again, Nirina On Mon, Sep 21, 2009 at 4:05 PM, Martin Weiss <martin.weiss1@gmx.de> wrote: > > <> > > See, just when I thought I knew Stata: -levels- is not the abbreviation for > -levelsof-, it is an out-of-date command, apparently with limited > functionality. I never noticed, but you did with your non-integer value... > So replace it by -levelsof- and it should work: > > > ************* > clear* > inp x > 1 > 3 > 4.5 > 4 > end > levelsof x > levels x > ************* > > > > HTH > Martin > > -----Ursprüngliche Nachricht----- > Von: owner-statalist@hsphsun2.harvard.edu > [mailto:owner-statalist@hsphsun2.harvard.edu] Im Auftrag von Nirina F > Gesendet: Montag, 21. September 2009 21:33 > An: statalist@hsphsun2.harvard.edu > Betreff: Re: st: AW: why is this graph all over the place? > > Thank you very much Martin. > I tried the example and it worked perfectly. When I tried with my > variables, the one that replaces mpg has one value that is not an > integer but is 42.6, therefore I got an error message: > levels varmain > varmain contains non-integer values > r(459); > I guess I should change the command -levels- with another one that > could list the values of varmain. > Also, I tried to recode varmain (42.6=43) but then I don't get > anything inside the new variable marg that keeps the marginal effects. > I am sure something is not right there because your example works > perfectly. I am going through each line to check. > > Nirina > > On Thu, Sep 17, 2009 at 6:19 PM, Martin Weiss <martin.weiss1@gmx.de> wrote: >> >> <> >> >> Try this and check it very carefully. I could not find such a picture in >> Long and Freese (2006), http://www.stata-press.com/books/regmodcdvs.html, > - >> which I regard as a bad sign. >> >> Also note I am using the old -mfx- here, as I have not fully gotten my > head >> round the -margins- command. Hence the -version- statement... >> >> >> ************* >> vers 10.1 >> >> qui{ >> sysuse auto, clear >> prob for price mpg rep78 /* >> */ headroom trunk weight >> >> ins mpg >> loc uniq= r(N_unique) >> >> su mpg, mean >> prgen mpg, from(`r(min)') /* >> */ to(`r(max)') /* >> */ gen(prob) n(`uniq') >> >> >> levels mpg >> >> loc i 1 >> gen marg=0 >> >> foreach level in `r(levels)'{ >> mfx, var(mpg) at(mpg=`level') >> mat A = e(Xmfx_dydx) >> replace marg=A[1,2] in `i' >> loc ++i >> } >> >> } >> >> tw (connected probp1 probx), /* >> */ xti("Mpg") ytit("Probability") /* >> */ name(prob, replace) nodraw >> >> tw (connected marg probx), /* >> */ xti("Mpg") ytit("Marginal Effect") /* >> */ name(marginal, replace) nodraw >> >> >> gr combine prob marginal >> ************* >> >> >> >> HTH >> Martin >> >> >> -----Ursprüngliche Nachricht----- >> Von: owner-statalist@hsphsun2.harvard.edu >> [mailto:owner-statalist@hsphsun2.harvard.edu] Im Auftrag von Nirina F >> Gesendet: Donnerstag, 17. September 2009 18:46 >> An: statalist@hsphsun2.harvard.edu >> Betreff: Re: st: AW: why is this graph all over the place? >> >> Dear Martin, >> >> Thank you very much for the clarification. >> How about graphing the marginal effects next to that graph? >> nrina >> >> On Thu, Sep 17, 2009 at 12:04 PM, Martin Weiss <martin.weiss1@gmx.de> > wrote: >>> >>> <> >>> >>> The -prgen- command holds all other covariates at their mean by default, >> so >>> my code has already taken care of your concern. To change the -title-s: >>> >>> ************* >>> sysuse auto, clear >>> prob for price mpg rep78 /* >>> */ headroom trunk weight >>> >>> ins mpg >>> loc uniq= r(N_unique) >>> >>> su mpg, mean >>> prgen mpg, from(`r(min)') /* >>> */ to(`r(max)') /* >>> */ gen(prob) n(`uniq') >>> >>> tw (connected probp1 probx), /* >>> */ xti("Mpg") ytit("Probability") >>> ************* >>> >>> >>> >>> HTH >>> Martin >>> >>> >>> -----Ursprüngliche Nachricht----- >>> Von: owner-statalist@hsphsun2.harvard.edu >>> [mailto:owner-statalist@hsphsun2.harvard.edu] Im Auftrag von Nirina F >>> Gesendet: Donnerstag, 17. September 2009 17:55 >>> An: statalist@hsphsun2.harvard.edu >>> Betreff: Re: st: AW: why is this graph all over the place? >>> >>> Thank you very much Martin for your help. It worked so well. >>> >>> I have a few questions: >>> >>> is it possible also to graph the marginal effects of just the mpg at >>> each value of mpg. I know if you calculate >>> . mfx >>> after >>> . prob for price mpg rep78 headroom trunk weight >>> >>> then you get the marg. effects at the mean value but I would like the >>> marginal effects at each value of mpg but keeping the other variables >>> at their mean. I am aware of the -at- option but it's just difficult >>> to graph it. >>> >>> Also, How would I change the name of the xaxis and yaxis of the previous >>> graph? >>> >>> Thank you very much, >>> >>> Nrina >>> >>> >>> On Thu, Sep 17, 2009 at 8:00 AM, Martin Weiss <martin.weiss1@gmx.de> >> wrote: >>>> >>>> <> >>>> >>>> For these purposes, Scott Long`s -findit spost- comes in handy. Of >> course, >>>> Long and Freese (2006), > http://www.stata-press.com/books/regmodcdvs.html, >>> is >>>> the canonical reference for what you are trying to achieve. Try this: >>>> >>>> >>>> ************* >>>> sysuse auto, clear >>>> prob for price mpg rep78 /* >>>> */ headroom trunk weight >>>> >>>> ins mpg >>>> loc uniq= r(N_unique) >>>> >>>> su mpg, mean >>>> prgen mpg, from(`r(min)') /* >>>> */ to(`r(max)') /* >>>> */ gen(prob) n(`uniq') >>>> >>>> tw (connected probp1 probx) >>>> ************* >>>> >>>> >>>> >>>> HTH >>>> Martin >>>> >>>> >>>> -----Ursprüngliche Nachricht----- >>>> Von: owner-statalist@hsphsun2.harvard.edu >>>> [mailto:owner-statalist@hsphsun2.harvard.edu] Im Auftrag von Nirina F >>>> Gesendet: Donnerstag, 17. September 2009 13:41 >>>> An: statalist@hsphsun2.harvard.edu >>>> Betreff: st: why is this graph all over the place? >>>> >>>> Dear all, >>>> >>>> I would like to graph the predicted probabilities of having foreign >>>> against mpg in order to highlight the slope(basically the marginal >>>> effects) at each value of mpg. >>>> I run the following but it is all over the place because I think it is >>>> giving me the predicted probabilities from different variables. >>>> Could you help me in this please. also if you could help me graph the >>>> marginal effects of mpg from this probit equation against each value >>>> of mpg. >>>> >>>> probit foreign price mpg rep78 headroom trunk weight >>>> predict pmpg, p >>>> sort mpg >>>> twoway line pmpg mpg >>>> >>>> Thank you veyr much, >>>> N >>>> * >>>> * 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/ >>> >>> >>> * >>> * 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/ >> > > * > * 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/ * * 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: why is this graph all over the place?***From:*Nirina F <fstata@gmail.com>

**Re: st: AW: why is this graph all over the place?***From:*Nirina F <fstata@gmail.com>

**Re: st: AW: why is this graph all over the place?***From:*Nirina F <fstata@gmail.com>

**Re: st: AW: why is this graph all over the place?***From:*Nirina F <fstata@gmail.com>

**Re: st: AW: why is this graph all over the place?***From:*Nirina F <fstata@gmail.com>

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