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From | Laurie Molina <molinalaurie@gmail.com> |
To | statalist@hsphsun2.harvard.edu |
Subject | Re: st: Question on interpretation of survey data: from the mean to the total |
Date | Sun, 12 Sep 2010 22:22:17 -0500 |
Thank you all very much. Exactly what i was looking for. Regards, LM On Sun, Sep 12, 2010 at 10:01 PM, Stas Kolenikov <skolenik@gmail.com> wrote: > I would go with > > svy : mean cars > > and > > svy : total cars if (household_head) > > if "cars" is the variable where the number of cars in the HH is > stored. It does not matter what was the purpose of the data > collection, but you need to have a clear notion of the units of > sampling, weighting, and analysis. If the latter matches the ave # > cars times expanded # of HHs, that's great, but you won't be able to > get the standard errors around it. With the above syntax, you will. > > On Sun, Sep 12, 2010 at 8:09 PM, Laurie Molina <molinalaurie@gmail.com> wrote: >> In my dataset each observation is a household and the weights are for >> households. >> In the survey there is a question about the number of cars of the household. >> So i am interested in the average number of cars of the HH. >> An also i am interested in the total number of cars owned by HH. >> >> To my understand it is ok to calculate the average number of cars of >> the HH, even with >> summarize cars[weight=factor]. >> >> But if i get that mean, and i multiply it by the (expanded) number of >> observations (HH), is it ok to say that it is the total number of cars >> of the HH in the survey? >> >> Thank you very much again! >> >> >> On Sun, Sep 12, 2010 at 7:13 PM, Steve Samuels <sjsamuels@gmail.com> wrote: >>> -- >>> >>> In advance I would say that you should create a data set in which >>> each observation is a HH and the weight is an appropriate HH weight. >>> However to advise you further with some assurance, we would need to >>> know how the weights were computed-was there post-stratification or >>> "raking", for example and details about the design (clusters, stages >>> is too vague). including the -svyset- statement. Your current >>> approach is almost certainly wrong, because the denominator for -svy: >>> mean- will be individuals, not HH; it will be biased, because larger >>> HH will contribute more observations. >>> >>> Steve >>> >>> Steven J. Samuels >>> sjsamuels@gmail.com >>> 18 Cantine's Island >>> Saugerties NY 12477 >>> USA >>> Voice: 845-246-0774 >>> Fax: 206-202-4783 >>> >>> >>> >>> On Sun, Sep 12, 2010 at 2:50 PM, Laurie Molina <molinalaurie@gmail.com> wrote: >>>> Dear all, >>>> I have a question on the interpretation of survey data. >>>> There is a survey in which the analysis units are the households and >>>> its members. >>>> Using the command svyset i have set the design characteristics of the >>>> survey: clusters, two stages, stratification and probabilistic. >>>> And i have asked stata for the mean of the number of cars in the households. >>>> Is it all right if i multiply the mean of the number of cars in the >>>> households by the expanded number of households to get the total >>>> number of cars of the households? >>>> Or does it depend on wheter the survey was designed to get the total >>>> number of cars of the households? >>>> Thank you very much in advance. >>>> Laurie >>>> * >>>> * 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/ >> > > > > -- > Stas Kolenikov, also found at http://stas.kolenikov.name > Small print: I use this email account for mailing lists only. > > * > * 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/