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*** This program samples observations from FILEPATH and returns the mean and count 
*** of VAR for REPNUM samples of size SAMPSIZE
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*** FILEPATH ***
use "E:\Course\Datasets\EMS\perulung_ems.dta", clear

*** Program definition ***
capture program drop mymean
program define mymean, rclass
	syntax [varname]

	*** FILEPATH ***
	use "E:\Course\Datasets\EMS\perulung_ems.dta", clear

	*** SAMPSIZE ***
	sample 10, count

	return local varname 'varlist'
		quietly {
			*** VAR ***
			summarize fev1
				return scalar mean = r(mean)
				return scalar N = r(N)
		}
end

*** Start simulation ***
simulate "mymean fev1" mean=r(mean) N=r(N), reps(100) dots

*** Summarize simulation results ***
label variable mean "Mean Forced Expiratory Volume (liters)"
label variable N "Number of observations drawn for each sampling replication"
histogram mean, frequency ylabel(2(2)20) xlabel(1.2(.1)2) ///
	ytitle(, margin(small)) xtitle(, alignment(middle) margin(medsmall)) ///
	title(Samping Variation) normal
summarize mean, detail

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