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From |
Lopa Chakraborti <[email protected]> |

To |
"[email protected]" <[email protected]> |

Subject |
st: RE: re: problem using predictnl after obtaining non-linear estimates |

Date |
Sun, 26 Oct 2008 11:40:59 -0400 |

I tried using nlcom without using any of the Xs and it seems to generate only a constant. It seems that only the point estimates of the parameters are being used and not the variance covariance matrix. nlcom (bod1 : ($K2/($K1-$K2))*exp(-$K1)*(exp(-$K2)-exp(-$K1))) bod1: (.0014539294546791/(.0009593881362685-.0014539294546791))*exp(-.0009593881 > 362685)*(exp(-.0014539294546791)-exp(-.0009593881362685)) ------------------------------------------------------------------------------ downstrea~04 | Coef. Std. Err. t P>|t| [95% Conf. Interval] -------------+---------------------------------------------------------------- bod1 | .0014508 . . . . . ------------------------------------------------------------------------------ Any help on this would be greatly appreciated. ________________________________________ From: [email protected] [[email protected]] On Behalf Of Kit Baum [[email protected]] Sent: Sunday, October 26, 2008 10:23 AM To: [email protected] Subject: st: re: problem using predictnl after obtaining non-linear estimates <> Lopa said Upon inserting the @ symbol it gives me a error message: nl wqfinalnoseasonfinal3 @ downstreamwaterqualityfoia04, nparameters(90) @ invalid name r(198); Is it because I work with Stata 8.2 version? From -help whatsnew8to9-: 10. Existing command nl has a new syntax that makes estimating nonlinear least-squares regressions easier. For most models, estimation is now as easy as typing the nonlinear expression. Full programmability has been retained for complex models, and the old syntax continues to work. nl also now supports robust (Huber/white/sandwich) and cluster-robust SE and VCE estimates, including two popular adjustments that can dramatically improve the small-sample performance of robust SE and VCE estimates. A number of new reporting and estimation options have also been added. See [R] nl. You may be right that the syntax of -nl- is different now. However you will have to find someone who has Stata 8.2 handy to assist with your program. I have Stata 9 on one machine, but have long since removed Stata 8.2. I have no idea how the old syntax of a function evaluator program differs (although I think it is the same in versions 9 and 10). Kit Baum, Boston College Economics and DIW Berlin http://ideas.repec.org/e/pba1.html An Introduction to Modern Econometrics Using Stata: http://www.stata-press.com/books/imeus.html * * 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/

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