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From |
Austin Nichols <austinnichols@gmail.com> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: Quintiles |

Date |
Thu, 9 Aug 2012 14:00:23 -0400 |

Leonardo Jaime Gonzalez Allende <leonardo.gonzalez@ine.cl>: Try this example out: sysuse auto, clear keep price weight ren price y sort y g s=sum(weight) g c=(s)/(s[_N]) g qbreak=0 g w2=. qui foreach l in 20 40 60 80 { replace qbreak=1 if c>=`l'/100 & c[_n-1]<`l'/100 replace w2=s-(`l'/100*s[_N]) if c>=`l'/100 & c[_n-1]<`l'/100 } g w1=weight-w2 g id=_n expand 2 if w2<. g wt=weight bys id: replace wt=w1 if _n==1 & w1<. by id: replace wt=w2 if _n==2 g sum=sum(wt) g cum=sum/sum[_N] l if qb==1 On Wed, Aug 8, 2012 at 3:44 PM, Leonardo Jaime Gonzalez Allende <leonardo.gonzalez@ine.cl> wrote: > Yes, Maarten, you are right, sorry for writing you directly. > > I don't was planning to cut a person or household in many parts. The question was about a possible adjustment to the weight factor, if the observation of the sample is the cut point of the quintile. > > If I sort the households of a sample by their incomes, a household "x" could represents 300 households but the accumulated frequency of the population is e.g. 20,02%. > > My question was if there is an efficient way (command) to repeat the observation and adjust weight factor as follow: > > the same household "xa" now represents 280 households and now the accumulated frequency of the population is e.g. 20% (exactly) (leaving to the first quintile). > > the same household "xb" (the other part) represents 20 households accumulating a frequency of 20,02% of the population (changing to the second quintile this part). > > Regards, > > Leonardo > > -----Mensaje original----- > De: Maarten Buis [mailto:maartenlbuis@gmail.com] > Enviado el: Miércoles, 08 de Agosto de 2012 12:41 > Para: statalist@hsphsun2.harvard.edu > Asunto: Re: st: Quintiles > > --- Leonardo Jaime Gonzalez Allende asked: >>>> I'm trying to divide a sample of households (expanded) >>>> into quintiles using the xtile command. I want to create >>>> 5 groups with the exactly same quantity of population, >>>> but using the xtitle command, the quantity of households >>>> in each quintil is very slightly different to 20% when the >>>> number of observations isn't exactly dividable by 5. >>>> Do you know any command to divide the population >>>> (sample expanded) into 5 groups of exactly same weight? > > --- I answered: >>> That is logically impossible. > > -- Leonardo Jaime Gonzalez Allende wrote me privately: >> sorry for write you directly, but I like to know, why is >> logically impossible separate the population (by >> incomes) in 5 groups of the same weith? > > Don't sent such follow-up questions privately. If you find my answer > puzzling, than chances are that someone else who is following this > discussion finds that too. This is explained in the Statalist FAQ. > > Think of it this way: How can you divide 6 persons in 5 equally sized > groups? You could assign one person to each group, and than you are > left with one person. If you could split the remaining 1 person up > into 5 1/5th persons, than we could create 5 equally sized groups. > However, that is impossible (or rather bloody, if we take that too > literally). So given the inherently discrete nature of the number of > observations you cannot divide your data up into 5 groups of exactly > the same size if the number of observations in not dividable by 5. > > -- Maarten * * 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: Quintiles***From:*Leonardo Jaime Gonzalez Allende <leonardo.gonzalez@ine.cl>

**References**:**st: One Step and 2 step GMM***From:*muneer <mkmmuneerbabu@gmail.com>

**st: xtreg check for outliers***From:*Dalhia <ggs_da@yahoo.com>

**st: RE: xtreg check for outliers***From:*"Jacobs, David" <jacobs.184@sociology.osu.edu>

**st: Quintiles***From:*Leonardo Jaime Gonzalez Allende <leonardo.gonzalez@ine.cl>

**Re: st: Quintiles***From:*Maarten Buis <maartenlbuis@gmail.com>

**Re: st: Quintiles***From:*Maarten Buis <maartenlbuis@gmail.com>

**RE: st: Quintiles***From:*Leonardo Jaime Gonzalez Allende <leonardo.gonzalez@ine.cl>

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