My data consist of unbalanced Panel data with the identifier gvkey_num fyear, fyear consists of the years 2010 till 2014. Further, the location of the company is given My question is if it is possible to take a random sample of 5 companies (gvkey_num) and to have all the fyear (all observations) of that company and not only of a single year. Example: If i wanted to have a random sample size of 2. I would like to have for example a sample of AVX CORP from 2010 to 2014 and Pfeiffer from 2010 to 2014. Another example is a random sample size of 2 which consist of ADC TELECOMMUNICATION year 2010 and ABOT LABORATORIES from fyear 2010 2011 2012 2013 2014.
My second question is it also possible to take a random sample panel data just as mentioned above but then for every loc(country) we take a random sample of 2 companies with their fyears. An example would be ADC TELECOMMUNICATION with fyear 2010 and ABOT LABORATORIES with fyear 2010 2011 2012 2013 2014. (Both from the USA) and 2 random samples from DEU which will result in PFEIFFER 2010 2011 2012 2013 2014 and NOVALED 2010 2011. (Both from DEU). If this isn't possible I would just make subsets of each country and make random samples just as in question 1 and later append them.
My database consists of 43 countries and 28,645 observations. I don't know how many firms there are in my data. I would also like to know how to count this.
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Example database:
gvkey num | fyear | conm | loc |
1013 | 2010 | ADC TELECOMMUNICATIONS INC | USA |
1072 | 2010 | AVX CORP | USA |
1072 | 2011 | AVX CORP | USA |
1072 | 2012 | AVX CORP | USA |
1072 | 2013 | AVX CORP | USA |
1072 | 2014 | AVX CORP | USA |
1078 | 2010 | ABBOTT LABORATORIES | USA |
1078 | 2011 | ABBOTT LABORATORIES | USA |
1078 | 2012 | ABBOTT LABORATORIES | USA |
1078 | 2013 | ABBOTT LABORATORIES | USA |
1078 | 2014 | ABBOTT LABORATORIES | USA |
63265 | 2010 | PFEIFFER VACUUM TECHNOLOGY | DEU |
63265 | 2011 | PFEIFFER VACUUM TECHNOLOGY | DEU |
63265 | 2012 | PFEIFFER VACUUM TECHNOLOGY | DEU |
63265 | 2013 | PFEIFFER VACUUM TECHNOLOGY | DEU |
63265 | 2014 | PFEIFFER VACUUM TECHNOLOGY | DEU |
3440 | 2010 | NOVALED AG -ADR -REDH | DEU |
3440 | 2011 | NOVALED AG -ADR -REDH | DEU |
Thanks!
Alexis da SilvaM
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