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From |
Maarten buis <maartenbuis@yahoo.co.uk> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: Fwd: st: Illustrate SRS in a graph |

Date |
Mon, 20 Sep 2010 07:49:29 +0000 (GMT) |

--- On Fri, 17/9/10, Richard Ohrvall wrote: > Just an additional small question, is there some way that I can > extract all the proportions and their lower and upper bonds > from the simulation by using some sort of loop? I have made it by > repeating the code for each group, i.e. [x:1], [x:2] and so on. But to > make the code a bit leaner when I have many groups I assume there is some > way to loop this, but my tries with -foreach var- did not work > well. Any suggestions? If you want lean code and accomodate many groups, you'll have to make the loop work. Here is one example, it still contains a loop, only now outside the simulation program. *------------------- begin example -------------------- program drop _all program define sim, eclass // create population drop _all set obs 10000 gen x = cond(_n <= 500, 1, /// cond(_n <= 5000, 2, 3)) // draw a 1% sample without replacement sample 1 // estimate the proportions and return the results proportion x matrix b = e(b) matrix V = e(V) local df = `e(df_r)' ereturn post b V ereturn scalar df = `df' end // repeat this 20 times and store the results in a dataset simulate _b _se df=e(df), reps(20) : sim //graph the results gen sample = _n forvalues i = 1/3 { gen lb_`i' = x_b_`i' - invttail(_eq2_df,0.025)*x_se_`i' gen ub_`i' = x_b_`i' + invttail(_eq2_df,0.025)*x_se_`i' } twoway scatter sample x_b_1 || /// scatter sample x_b_2 || /// scatter sample x_b_3 || /// rcap lb_1 ub_1 sample, horizontal || /// rcap lb_2 ub_2 sample, horizontal || /// rcap lb_3 ub_3 sample, horizontal xline(.05 .45 .5) *-------------------- end example -------------------------------- Hope this helps, Maarten -------------------------- Maarten L. Buis Institut fuer Soziologie Universitaet Tuebingen Wilhelmstrasse 36 72074 Tuebingen Germany http://www.maartenbuis.nl -------------------------- * * 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/

**References**:**Fwd: st: Illustrate SRS in a graph***From:*Richard Ohrvall <richard.ohrvall@gmail.com>

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