day3prlm

day3prlm - 1/26/12 PADP 8130: Linear Models Math...

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Unformatted text preview: 1/26/12 PADP 8130: Linear Models Math Review PRACTICE Angela Fer:g, Ph.D. Ge?ng Stata output into Excel •  If it is from sum or tab, highlight the table and copy using the shiL key •  If it is a regression, use outreg2 –  Open up a do file –  Name it, put top lines in, open dataset –  Run regression: reg faminc educhd! –  Put in outreg2 command: !outreg2 using regs1, excel replace! –  Run next regression: reg –  Put in outreg2 command faminc educhd agehd !outreg2 using regs1, excel! –  Within excel, open up regs1.xml ! 1 1/26/12 Some useful data management commands: append, merge & reshape •  Append – combine 2 data sets by stacking the observa:ons; it just increases the sample size •  Merge – combine 2 data sets by increasing the variables observed on each observa:on; it increases what you know about each observa:on –  So, if you made your beau:ful datafile for your research project and it took hours, and then you realize that you are missing one variable, merge can fix it. •  Just get the addi:onal variable needed in a separate data file. •  Merge it with the new data file. Reshape Reshape: converts data from long to wide, or vice versa e.g. one observa:on has informa:on on husbands and wives, but you want husbands and wives to each be their own observa:on – you need to reshape from wide to long id person Wagehd id Wagehd wagewf 1 1 100000 1 100000 10000 1 2 10000 2 35000 15000 2 1 35000 2 2 15000 2 1/26/12 Try it out •  Go to the psid data center and find the wage data for the head and wife – make the data set •  Merge it with day2.dta Use day2.dta Sort fid Save day2.dta Use wage.dta Sort fid Save wage.dta clear Use day2.dta Merge fid using wage.dta Save day3.dta, replace Then reshape •  Reshape long so husbands and wives are separate observa:ons Use day3.dta Reshape long wage, i(fid) j(person) Save day3r.dta, replace Make sure beginning of variable name is same for both husband and wife. Fid is the unique iden:fier in the wide format. Person is a new variable that will be created to iden:fy the husbands vs. the wives for each fid. 3 ...
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This note was uploaded on 03/28/2012 for the course PADP 8130 taught by Professor Fertig during the Spring '12 term at LSU.

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