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

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

Subject |
st: Re: Randomly selecting variables in panel, collapsing, and simulating |

Date |
Sat, 13 Jun 2009 18:06:58 +0200 |

<>

********** clear* input i y x z n 1 5 8 3 1 1 9 10 5 2 1 8 12 6 3 1 6 9 4 4 2 5 7 2 1 2 9 13 4 2 2 8 8 7 3 2 6 8 6 4 2 8 8 7 5 2 8 8 7 6 3 5 7 2 1 3 9 11 7 2 3 8 11 5 3 end compress list, noobs /* get groups */ gen random=runiform() sort i random by i: gen byte group=/* */cond(_n<=_N/2,1,2) l, noo sepby(i) drop random collapse (mean) y x z, /* */by(i group) l, noo sepby(i) ********** HTH Martin _______________________

To: <statalist@hsphsun2.harvard.edu> Sent: Saturday, June 13, 2009 3:19 PM

Hi:I want to do something that is quite straightforward, but don't yet havethe programming skills to do this, so I would appreciate some help.Basically, I want to select randomly within clusters, then collapse, thenestimate a regression model that I would like to simulate. I would liketo define it as an e-class program so that I can easily incorporate asimulation in there.I have the following data structure (I have added a line in-betweenclusters to facilitate viewing):i y x z n 1 5 8 3 1 1 9 10 5 2 1 8 12 6 3 1 6 9 4 4 2 5 7 2 1 2 9 13 4 2 2 8 8 7 3 2 6 8 6 4 2 8 8 7 5 2 8 8 7 6 3 5 7 2 1 3 9 11 7 2 3 8 11 5 3Where y is the dependent variable, and x and z are covariates (note, Ihave more covariates, so I would like to use something general that workseven with more covariates), "i" is the panel identifier and "n" is numberof observations in each cluster. Note that each cluster does not have thesame number of observationsI would like to do the following:1) by cluster (i.e., within in each cluster), randomly split theobservations into two groups, with an equal amount of observations (ifnumber of observations are even); if the number of observations are odd,then one of the group will have 1 more observation than the other. Thus, Iwould now have this:i y x z n g 1 8 12 6 3 1 1 5 8 3 1 1 1 6 9 4 4 2 1 9 10 5 2 2 2 9 13 4 2 1 2 5 7 2 1 1 2 8 8 7 3 1 2 8 8 7 5 2 2 6 8 6 4 2 2 8 8 7 6 2 3 5 7 2 1 1 3 8 11 5 3 2 3 9 11 7 2 2 2) collapse observations at the group level for each cluster to get: i g y x z 1 1 6.5 10 4.5 1 2 7.5 9.5 4.5 2 1 7.3 9.3 4.3 2 2 7.3 8 6.7 3 1 5 7 2 3 2 8.5 11 63) then I want to the data as below, so that I can regress the y of thefirst observation in each cluster to the x and z of the second observationin each clusteri y x z 1 7.5 9.5 4.5 2 7.3 8 6.7 3 8.5 11 2 4) once I have this I want to simulate it, using something like this: capture program drop sim version 10.1 program define sim, eclass [here is the code I would like to insert to make points 1-4 above run] simulate _b _se, reps(20) seed (123) : sim, foreach v in x z { gen t_`v' = _b_`v'/_se_`v' gen p_`v' = 2*(1-normal(abs(t_`v'))) Thank you. John. -- ____________________________________________________ Prof. John Antonakis Associate Dean Faculty of Business and Economics University of Lausanne Internef #618 CH-1015 Lausanne-Dorigny Switzerland Tel ++41 (0)21 692-3438 Fax ++41 (0)21 692-3305 Faculty page: http://www.hec.unil.ch/people/jantonakis&cl=en Personal page: http://www.hec.unil.ch/jantonakis ____________________________________________________ * * 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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**Follow-Ups**:**Re: st: Re: Randomly selecting variables in panel, collapsing, and simulating***From:*John Antonakis <john.antonakis@unil.ch>

**References**:**st: Randomly selecting variables in panel, collapsing, and simulating***From:*John Antonakis <john.antonakis@unil.ch>

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