[Date Prev][Date Next][Thread Prev][Thread Next][Date index][Thread index]

From |
"Scott Merryman" <smerryman@kc.rr.com> |

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

Subject |
Re: st: Re: Problems with -hetgrot- |

Date |
Sun, 14 Mar 2004 21:36:24 -0600 |

----- Original Message ----- From: "Richard Williams" <Richard.A.Williams.5@nd.edu> To: <statalist@hsphsun2.harvard.edu> Sent: Sunday, March 14, 2004 6:38 PM Subject: Re: st: Re: Problems with -hetgrot- > At 06:14 PM 3/14/2004 -0600, Scott Merryman wrote: > >Richard, > > > >I believe there is an error in Greene's text. As you reported, Greene > >gives the > >LR statistics as 120.915. However, if you compute this by hand, given the > >individual sigma^2, the result is: > > > >. disp 100*ln(15708.84) - 20*(ln(9410.91) + ln(755.85) + ln(34288.49) + > >ln(633.42) + ln(33455.51)) > >104.41512 > > > >which is what you and I got. > > I did the same thing! But if he has an error, I don't think that is where > it is. In Greene, 4th edition, p. 597, he says that iterated fgls (the > Model 3 I presented) can be used to compute the LR statistic. But, he also > says that "If only least squares results are available...[they may be > used], possibly with some loss of power in small samples." That is what > your above calculation does; it uses the least squares estimates rather > than the ML estimates. > > What Greene apparently does is use the estimate of sigma from the OLS > estimates (15708.84) with the ML estimates for the group sigmas. The > calculation (using the #s reported on p. 598_ is > > . disp 100*ln(15708.84) - 20*(ln(8657.72) + ln(175.80) + ln(40210.96) + > ln(1240.03) + ln(29825.21)) > 120.92892 > > What I don't understand is why he is using the 15708.84 from the least > squares estimates, rather than using a ML estimate of sigma. This would > seem to be inconsistent with what he says on the middle of p. 597. > Richard, Thanks, I breezed right past this when looking at table 15.1. Scott * * For searches and help try: * http://www.stata.com/support/faqs/res/findit.html * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/

**References**:**st: updates to -egenmore- on SSC***From:*"Nick Cox" <n.j.cox@durham.ac.uk>

**st: Problems with -hetgrot-***From:*"Clive Nicholas" <Clive.Nicholas@newcastle.ac.uk>

**Re: st: Re: Problems with -hetgrot-***From:*Richard Williams <Richard.A.Williams.5@nd.edu>

**Re: st: Re: Problems with -hetgrot-***From:*Richard Williams <Richard.A.Williams.5@nd.edu>

- Prev by Date:
**st: Re: Score test** - Next by Date:
**Re: st: Date: Sun, 14 Mar 2004 21:07:28 -0500** - Previous by thread:
**Re: st: Re: Problems with -hetgrot-** - Next by thread:
**Re: st: Re: Problems with -hetgrot-** - Index(es):

© Copyright 1996–2017 StataCorp LLC | Terms of use | Privacy | Contact us | What's new | Site index |